Onion soup is a classic feat of French culinary magic, requiring little more than humble onions, time and patience. It’s a soup of nostalgia — at least, for me — once featured at Pal’s Cabin Steakhouse in West Orange, N.J., where it came in a brown crock with two spoons to better manage the blistering cap of molten Gruyère. Ordering this grown-up dish, I made showy use of my high school French.
The other day, as the subzero temperatures kept me from the grocery store, I realized I had plenty of onions left in the pantry and hours to kill. Voilá, onion soup.
I chose a mix of sweet yellow and stronger white onions for a range of flavors and bypassed the red ones which can be bitter and turn a muddy, reddish-brown when cooked. Those are best saved for salad. I opted for shallots instead of garlic, because they are milder and tend not to burn.
While some books suggest cooking the onions until they’re a deep, dark mahogany color, Julia Child’s “Mastering the Art of French Cooking” specifies that they be an “even, deep golden brown,” which results in them being soft and very sweet. There’s a fine line between that and cooking them so long that they become too dark, which results in them being bitter.
You can cook the onions in oil, but I’ve found that butter works very well. The natural sugars enhance the onions’ sweetness and their color, while enriching the whole mess with a silky texture. Plan on spending about 30 to 45 minutes to sauté them to the right stage. Though some recipes add sugar and flour, I think these tend to make the soup too sweet and thick, so leave them out.
I’ll argue in favor of homemade stock, either beef or chicken, for the best flavor. When I’m out of my own stuff, I’ve found really good housemade options at butcher shops (Clancey’s Meats and Fish; Lowry Hill Meats; St. Paul Meats) as well as at food co-ops.
These housemade versions are delicious, well worth the price and far better-tasting than the boxed varieties, which can be salty. Finish the soup with a generous splash of sherry to add depth and complexity; a little balsamic vinegar will also do the trick.
When the wind blows hard and we’re stuck inside, Soupe à l’Oignon Gratinée, innately frugal, simple, elegant and unpretentious, is a perfect soup du jour.
Beth Dooley is the author of “In Winter’s Kitchen.” Find her at bethdooleyskitchen.com.