Carabaccia is an ancient Tuscan onion soup, going back to the Renaissance. They say it was a favorite of Leonardo da Vinci.
4large white onions, chopped
1tablespoonall purpose flour
1/4cupcognac or cream sherry
Salt and freshly ground black pepper
8slicesciabatta bread (thick slices)
8ouncesFontina cheese, sliced or grated
Melt the Plugrá Butter in a large stockpot over medium heat. Add the onions and sauté until golden, 8-10 minutes. Stir in flour, scraping the bottom of the pot to incorporate everything.
Splash the pan with sherry and add the thyme. Stir to combine and allow the liquid to reduce, about 4 to 5 minutes. Add the beef stock, cognac and salt and pepper to taste and cook for 30 minutes.
Preheat the broiler. Toast the ciabatta, rub each side with garlic and place each slice in the bottom of soup cup or bowl. Add soup to each cup, top with cheese and place the cups on a rimmed baking sheet or in a large baking pan.
Place the pan under the broiler until cheese melts and the soup is boiling hot, about 1 minute. Serve immediately.