From ‘purple’ onions to garlic bulbs: Key insights on alliums so you can elevate your cooking

Plus, learn a new trick to avoid crying while you cut onions.
Jan. 24, 2024
Most people consider red (also called “Bermuda” or “purple”) onion to be delicious raw. Indeed, it is.
Most people consider red (also called “Bermuda” or “purple”) onions to be delicious raw. How to optimize recipes with onions. Photo by Bill St. John, for UCHealth.

Is it OK to sub out a white for a yellow onion in just any preparation? Or, for that matter, a red or purple onion for a yellow? Those little green sprouts inside a clove of garlic: heard they’re bitter, right? Well, are they?

Why do Americans, by and large, have two names — “scallion” and “green onion”— for what appear to be quite the same thing? What do you do when you take a leek? Grill it? Use it in soup?

Do your eyes always tear up when cutting onions? Mine do. Or, I should say, “did.” A couple of years ago, I figured out how to keep the peepers dry when prepping my onions.

These are questions, common questions, about the genus Allium, a vast umbrella of odiferous and flavor-carrying plants that we cooks know as the various onions, garlic, chives, the shallot, leeks, and the scallion with which we cook. It is not inconsequential that their overall name in the kitchens of the pros is “aromatics.”

“Scallion,” or, “green onion.” These two are the same thing, just going by different names to different people or peoples. Use whichever name is your vernacular. Green onions are truly “green,” that is, they are immature, not fully grown, onions. Some Australians and Québécois even call what we call a “scallion,” a “shallot.”

Leeks resemble very large scallions. Their white section is generally milder in flavor and aroma than either the flesh of the onion or the shallot. The most famous dish made with leeks is the potato-based soup Vichyssoise (interestingly, so-named, an American recipe, invented in the early 1900s by Louis Félix Diat, a French-born chef at the Ritz-Carlton Hotel in New York City). The soup has nothing to do with Vichy, France, although Diat does: he was born near there.

By and large, the common leek is too thick to grill successfully or profitably, although thinner (less mature) specimens might work. At Asian produce markets, you might find an allium thicker than a scallion and thinner than a leek. I’ve enjoyed grilling them. They go by different names such as “large green onion” or dàcōng, its Chinese name.

How to cut an onion without crying

When cutting up any allium, but especially onions, I learned a trick that helps me “cry” less. Place a burning candle on either side of the cutting board. The flames eat up the volatilized sulfuric compounds that irritate and burn the cook’s eyes. At least, it works for BSJ.

What onion to use

So many onions from which to choose the proper one! The most common, yellow onions, are plentiful and all-purpose—not as terrific raw as other onions, but passable thus, and always sweet when cooked down or for a long time. Here’s how to cut up one and a French onion soup recipe in which to use it.

Here in Colorado, white onions are popular in Mexican cooking, also raw and either chopped or sliced. They’ve got more “onion-y” flavor and can be quite pungent, but they don’t hold up in long cooking the way that yellows do.

Most people think the red (also called “Bermuda” or “purple”) onion to be delicious raw, and indeed, that’s how you’ll often find it (atop a burger patty, for example, or in a Greek salad). They lose their crimson on cooking, so keep that in mind. Some folks think that red onions have gotten stronger and punchier over the last decade. I’ve no research that I can find (nor have done) to back up that claim. 

Sweet onions, as their name says, are much less pungent than other regularly available onions of whatever color. The two most famous monikers are Walla Walla (from Washington State) and Vidalia (from the State of Georgia). In Colorado, we grow a delicious sweet onion called the Colorado Sweet, though it may be difficult to find. All sweet onions have a higher sugar content and more water than other alliums, can easily be eaten raw, and turn even sweeter on long cooking.

Other great tips and recipes from Bill St. John.

The shallot is a sort of cross between a yellow and a red onion, but much smaller than either. It has lobes like the garlic bulb’s “cloves,” though they are much larger. Its delicate flavor and size lend it suitable for use raw in things such as a mignonette (for raw shellfish: a simple sauce of vinegar, shallot, and black pepper) or adding just a whisper of allium flavor to quick sautés and the like.

The chive is basically the hollow-stemmed “leaf” of a very small onion; its blossom, if you can find it still attached, is even better eating or flavoring.

Using and cooking garlic

“Always remove the sprouting green parts of the garlic clove,” goes the convention, “because they are bitter.” Turns out, they are not.
“Always remove the sprouting green parts of the garlic clove,” goes the convention, “because they are bitter.” Turns out they are not. Photo by Bill St. John, for UCHealth.

Finally, garlic, about which I have written much and eaten even more. Garlic gets bitter if you severely brown it or burn it. Garlic is low in both water and fructose, so it burns easily. But in certain ways of cooking, it gets mellower, sweeter, and nuttier when cooked at length, especially in liquids such as stews or braises.

You’ll hear from many people (or read widely) that the small green sprouts that emerge from stored cloves of garlic are themselves bitter and ought to be excised from each clove before cooking. I have not found that necessary; the sprouts, in fact, are not bitter. They are new growth, after all, and isn’t that usually mild and even sweet?

Moreover, of most interest to the scientist in me (such as he is), is the compound allicin which gives garlic its “garlickiness,” its pungency, piquancy, and aroma. Allicin is formed when the cells in a raw garlic clove are broken (sliced, minced, crushed, etc.) and when alliin and alliinase — two compounds separated within garlic — are then allowed to combine.

Allicin is highly scorchable and, when burnt, is very bitter. So, the byword is “Do not excessively brown or burn raw garlic,” especially over high or medium-high heat.

Storing onions

Buy heads of garlic and shallot that are firm and solid; any empty spaces behind their outer “paper” signals dehydration and possible deterioration within.

Store allium bulbs such as garlic, onions, shallots and the like outside the refrigerator in a dark, airy space. Hanging them in a basket by the stove isn’t a good idea; keeping them in the refrigerator is worse.

More on storing and preparing vegetables, and bonus recipes, read these Bill St. John articles:

How to best store fresh fruits, vegetables & herbs

Tested: food rules for preparing vegetables

Do not wash scallions or leeks (or similar long, white-and-green) alliums until use. To keep, wrap in paper toweling, then place in a plastic bag and store in the refrigerator’s vegetable bin. Wash and peel on using.

Treat chives like flowers: Wash them on returning from the grocer’s; spin or shake fairly dry; cut off about 1 inch from the stem end and place in a container with a couple of inches of water. Then, cover with a light plastic bag (such as a grocer’s vegetable bag) and keep on a shelf in the refrigerator.

One of the more famed of all Roman pasta preparations—aglio e olio. As the name has it, mere “garlic and olive oil” for the pasta’s sauce.
One of the more famed of all Roman pasta preparations — aglio e olio. As the name has it, mere “garlic and olive oil” for the pasta’s sauce. Photo by Bill St. John, for UCHealth.

Pasta aglio e olio recipe

Doesn’t get any more late-night Italian than this; in Rome, they just order “aio e oio” — said so quickly, it’s like one word (“ay-yoyo”). The main flavoring comes from the olive oil, so be sure to use the best you have. This recipe keeps the slivered garlic from burning, something devoutly to be avoided. This version is also a variation on the base recipe which merely sprinkles parsley atop. One more thing: traditionalists eschew grated cheese, although you may find some Pecorino Romano to your taste. Makes 4 servings.


1 pound long-form dried pasta (bucatini, spaghetti, linguine, etc.; see note)

1/2 cup top-quality extra virgin olive oil from Italy

3 garlic cloves, sliced see-through-thin or minced

1/2 teaspoon dried red chile flakes, or 4-5 small dried red chiles (or omit altogether)

1/2-3/4 cup minced fresh green herbs, to taste (parsley, chive, basil, dill, thyme, etc.)


Bring a large pot of well-salted water to the boil. In a skillet, over medium heat, pour the olive oil, garlic slivers, and chiles or flakes. The second that the garlic sizzles, say the Pledge of Allegiance, then take the skillet off the heat and set it aside on the stove.

Cook the pasta until it is al dente; drain it, reserving 1 cup of the pasta water, and return the pasta to the large pot.

Meanwhile, just before the pasta is done, reheat the garlic and oil mixture and, when the oil shimmers, toss in all the minced herbs and stir well. The herbs will take up the oil and form a rich, thick sauce. Add the sauce to the pot with the pasta, combining everything well (a pair of tongs works best here). If it appears dry, use spoonfuls of the pasta water to loosen it.

Note: The traditional recipe calls for linguine; however, you may use any long-form pasta, but preferably dried. Aglio e olio is better with dried pasta than with fresh, egg-based pasta because these latter tend to soak up the olive oil too facilely and make the overall dish somewhat dry. 

Baked Vidalia Onion recipe

Baked Vidalia onions look like giant chocolate kisses — and, when cooked, they’re nearly as sweet. Photo by Bill St. John, for UCHealth.
Baked Vidalia onions look like giant chocolate kisses — and, when cooked, they’re nearly as sweet. Photo by Bill St. John, for UCHealth.

The recipe is for the onion called “Vidalia,” from the state of Georgia. You may use other sweet onions, of course, such as a Washington State Walla Walla or, to keep it real, a Colorado Sweet. Makes 1 but is easily multiplied. A whole onion is a suitable serving for 1 person, especially if accompanied by other foods, such as a baked potato or a green salad, to round out the service.


1 Vidalia onion

1 vegetable, chicken, or beef bouillon cube or 3/4 teaspoon of the same in paste form

1–2 tablespoons butter

Freshly ground black pepper


Preheat oven to 350 degrees. Peel the onion, leaving the root intact. If the onion sits level, leave it alone. If not, cut a thin slice off the root to create a flat bottom. Use a paring knife to cut a wide, 1-inch-deep cone into the top of the onion. Insert a vegetable, chicken, or beef bouillon cube (or the equivalent in paste form) into the hole.

Fill the rest of the hole with butter, about 1-2 tablespoons. Season with pepper. Place the filled onion on a sheet of foil large enough to encase it. Wrap the onion in foil, bringing the edges up in the center. Twist the foil together to seal in the onion (it will resemble a giant Hershey’s Kiss). 

Place the foil-wrapped onion on a baking sheet. Bake for 45-60 minutes, until the onion is tender. Serve warm. (Baking times remain the same for multiple onions.)

Sweet Onion Confit recipe

Translated by Bill St. John from Makes between 2-3 cups. 


1 pound sweet onions (about 2 large or 3 medium), peeled and thinly sliced along the “poles”

Extra virgin olive oil

Kosher or sea salt

3 tablespoons aged balsamic vinegar

1 teaspoon cane sugar


Over medium-high heat place a large heavy-bottomed pot or Dutch oven. Place 4 tablespoons oil into the pot and, when it slightly shimmers, add all the onions, stirring them to coat with oil. Sprinkle with salt.

Brown the onions over medium to medium-high heat, making sure they don’t burn but merely become more and more golden brown, anywhere from 40-60 minutes, stirring occasionally. (If some burning occurs, deglaze the burn with a splash of water, not oil.) When the onions are very soft and deeply golden brown, add the vinegar and stir in. Sprinkle on the sugar. Cook over medium or medium-low heat for an additional 15 minutes, stirring at least twice.

Notes: You may cover the cooking onions for part of the time, lowering the heat during that period. You may use other sorts of vinegar, such as apple cider vinegar, if you do not wish the confit as dark. You may also add other flavorings such as 1 tablespoon whole-grain Dijon mustard, or 1 tablespoon honey, or 1/4 cup dry red wine or Port.

Reach Bill St. John at [email protected]

About the author

For more than 40 years, Bill St. John’s specialties have been as varied as they are cultured. He writes and teaches about restaurants, wine, food & wine, the history of the cuisines of several countries (France, Italy, Spain, Belgium, and the USA), about religion and its nexus with food, culture, history, or philosophy, and on books, travel, food writing, op-ed, and language.

Bill has lent (and lends) his subject matter expertise to such outlets as The Rocky Mountain News, The Denver Post, The Chicago Tribune, 5280 Magazine, and for various entities such as food markets, wine shops, schools & hospitals, and, for its brief life, Microsoft’s In 2001 he was nominated for a James Beard Award in Journalism for his 12 years of writing for Wine & Spirits Magazine.

Bill's experience also includes teaching at Regis University and the University of Chicago and in classrooms of his own devising; working as on-air talent with Denver's KCNC-TV, where he scripted and presented a travel & lifestyle program called "Wine at 45"; a one-week stint as a Trappist monk; and offering his shoulder as a headrest for Julia Child for 20 minutes.

Bill has also visited 54 countries, 42 of the United States, and all 10 Canadian provinces.