When it's cold outside and you've ducked into a French bistro, nothing spells c-o-m-f-o-r-t like a hot bowl of French onion soup - right down to the bread-borne melted Gruyere floating on top. But that dish is purely a restaurant indulgence, right? Making it at home calls for the cook to stir the onions on top of the stove for an hour or more to coax them into a state of tender, golden silkiness. That is, unless you've enlisted the help of a slow cooker. Suddenly, there's no reason not to whip up the classic recipe in your very own kitchen.
The only serious work is slicing the onions, and yes, alas, doing so will make you cry ... unless you have goggles at hand or follow the accompanying TIP below.
This recipe is adaptable, and these substitutions make it an Italian onion soup rather than a French one: olive oil instead of butter, Italian cheeses instead of Gruyere and chopped parsley or thyme as a garnish. You can make it vegetarian by using vegetable broth and lactose-free by omitting the cheese. Worried that its heartiness may get lost in the process? Don't be. There's still that poached egg on top.
Ideally, you'll make this soup a full day ahead, which will give it all the time it needs to reach perfection in the slow cooker.
ITALIAN ONION SOUP
Yield: 6 servings
1/4 cup extra-virgin olive oil 3 pounds yellow onions, very thinly sliced 1 tablespoon minced garlic 1 teaspoon kosher salt, plus more as needed 6 sprigs fresh thyme 1 cup dry white wine 2 tablespoons sherry vinegar 6 cups low-sodium beef, chicken or vegetable broth 1 tablespoon fresh lemon juice Freshly ground black pepper 12 1/2-inch-thick, diagonally cut baguette slices 2½ ounces coarsely grated Italian fontina cheese 1/2 ounce finely grated Parmigiano-Reggiano cheese 6 large eggs Chopped parsley or thyme, for garnish
Combine the oil, onions, garlic, salt, thyme, wine and sherry vinegar in the slow cooker and stir to incorporate. Cover and cook on high for 7 hours, stirring quickly every couple of hours. Add the broth, cover and cook on high for 2 hours.
Discard the thyme sprigs and stir in the lemon juice; taste and season lightly with salt and pepper.
Preheat the oven to 400 degrees. Fill a large, straight-sided saucepan with 2 inches of water and bring to a boil over high heat.
Arrange the bread slices on a rimmed baking sheet in a single layer. Toast (middle rack) for 4 minutes, turning them over once.
Meanwhile, stir together the fontina and Parmigiano-Reggiano in a bowl. Top each toast with the cheese mixture, using all of it.
Break the eggs into individual ramekins or small bowls. Remove the saucepan of boiling water from the heat. Working quickly, pour the eggs one by one into the water, cover and let stand (off the heat) for about 2 minutes, or until the whites are set and the yolks are still jiggly (if you desired a more well done egg, leave it in for another minute). Transfer with a slotted spoon to a shallow bowl as they are done.
While the eggs are poaching, bake the fontina toasts (upper rack) for 2 minutes, or until the cheese has melted.
To assemble, ladle the soup into individual bowls, Top each portion with an egg and a sprinkling of parsley or thyme. Serve hot, with two toasts per portion, for dunking.
Tip: Slice the onions with the grain, not against it. Start by cutting off both ends of each onion and halving it from the stem through the root. Then peel the onion and lay both halves face down on the cutting board. Now, follow the ribs to slice the onions with the grain. This technique is less damaging to the onion's cells than slicing across the grain, which means it generates less gas that makes us cry. It also ensures that the slices retain their shape in the soup.