Leeks are in season from the winter through early spring and are a staple ingredient for many comforting dishes (like my creamy leek and mushroom pasta).
Leeks are part of the allium family - so similar to onions, shallots, chives, garlic, and so on. But they have a very nuanced, sophisticated taste (compared to harder notes of, say, a red onion). But that doesn’t mean it can’t be substituted! So, remember that each large leek makes a cup of chopped leeks and read on.
Green Onions or Chives
My favorite substitute for leeks are green onions or scallions. Green onions have a very similar flavor profile to leeks - they’re mild, but have the familiar onion / garlic taste.
Only issue is that you'll need a large number of scallions to make up for a leek (typically about 6 to 10 scallions to substitute a large leek). But, they are easily available and the closest flavor profile match! Chives also offer a similar flavor profile but are even smaller.
Shallots + Celery
Using shallots and celery together are your next best option. Shallots are a bit stronger than leeks, but milder than onions. So, when combined with celery, shallots are a great approximation for leeks. They’re also typically easy to find in most grocery stores.
Substitute 1 large leek, or a cup of chopped leeks with 1 large shallot (or 2 medium shallots) and 1 medium-sized celery stalk. In a pinch, you can also use either of those too. In that case, use 2 large shallots (or 4 medium shallots) or 2 medium-sized celery stalks instead.
White onions or Vidalia onions are another good alternative. They are quite easy to find in grocery stores, and because they're sweet, you can get quite close to the flavor. If you use yellow onions instead, I suggest slicing the onions and placing them in cold water for a few minutes to remove the bite so it’s more similar to leeks. Substitute 1 large leek with one medium sized onion.
Onion & Garlic Powder
Finally, if you’re all out of options, and just need to replace the flavor (but not the texture) you can throw a teaspoon each of onion and garlic powder (or either).
If you're using leeks alongside another ingredient in a soup (say a potato and leek soup), you can use green onions, shallots and celery or even regular onions. If you’re making a soup with the leek as the star, finding a substitute may be slightly more difficult. Make sure to sauté onions before adding to soup - this can help match the flavor.
You will discard the darker green parts and root of the leek and eat just the white and light green parts. The darker green parts can be cooked and tenderized, but I find they are better used for stocks.