January 16, 2012
The key to developing the deep flavors of traditional French onion soup while making it vegetarian is to cook the onions almost past amber, even allowing them to char a bit around the edges. The other key flavor-booster is to use porcini mushroom stock, something I tend to have on hand after the winter holidays. You can use any mushroom stock, but the porcini will bring the most flavor. If you only have vegetable stock, put 6 ounces of sliced or quartered mushrooms in a 4 inch square of cheesecloth, bundle and tie off with kitchen string. Add the mushroom bundle in with the onions after you add the stock
For the soup:
2 tablespoons canola oil
1 tablespoon butter
1 pound Vidalia onions, peeled and sliced 1/4 inch thick
4 sprigs of fresh thyme, tied together with kitchen string
1 bay leaf
2 teaspoons house salt
Black peppercorns in a pepper mill
2 teaspoons flour
1/2 cup white wine (Sauvignon or Chenin blanc)
2 cups mushroom
1 cup water
For the cheese toast:
2 1 ½ inch thick slices favorite artisan bread
2 teaspoons extra virgin olive oil
1 teaspoon salt, divided
1 1/2 cups grated Gruyère cheese, sharp as you like, divided
Set oven rack to center position. Heat oven to 375 degrees and line a baking sheet with parchment or a silicone mat.
Heat a 3-quart Dutch oven over medium high heat for 3 minutes. Add the oil and swirl to coat the bottom of the pan. Add the butter and cook until the foam from the butter has subsided. Add the onions and stir to coat with the oil and butter. Sprinkle in the salt and cook, stirring frequently until the onions begin to soften. Add the thyme bundle, bay leaf and several grinds of freshly cracked black pepper. Continue cooking, stirring occasionally until the onions are sticky and deep amber in color, 30 to 35 minutes. Deglaze the pan with the water, loosening the sticky onions and scraping up the fond in the bottom of the pan. Stir in the stock, lower the heat to medium and cover the Dutch oven. Let the soup simmer for 20 minutes.
Meanwhile place the bread on the prepared baking sheet. Drizzle each with 1 teaspoon oil and season with 1/2 teaspoon salt and freshly cracked black pepper. Bake the bread until it is evenly toasted, 4 to 5 minutes. Remove from the oven and set aside.
Heat the broiler.
For final preparation remove the mushrooms (if using), thyme bundle, and bay leaf and discard. Ladle the soup into 2 ovenproof crocks. Top each with a slice of toast and top each toast with an even layer of cheese
Place the crocks on the same baking sheet used to toast the bread and place on middle rack. Broil until the cheese is completely melted and light golden brown, 5 to 7 minutes
Let the French onion soup rest for 5 minutes before serving