This American twist on French onion soup is inspired by the Lipton's Onion Soup Mix sour cream party dip.
- 4 tablespoons (1/2 stick) butter
- 4 large onions, thinly sliced
- 2 to 3 leeks, trimmed, split lengthwise, sliced into 1/2-inch pieces, cleaned and dried
- 4 shallots, halved and sliced
- 4 cloves garlic, finely chopped
- 1 large fresh bay leaf
- About 1/2 teaspoon ground thyme
- Salt and coarse black pepper
- 1/4 cup dry sherry
- 2 tablespoons Worcestershire sauce
- 5 cups beef stock
- 1 cup creme fraiche
- Crusty French bread (grocery-store, soft-center, wider than baguette, about 3 to 4 inches cut into 1-inch-thick rounds/slices)
- Grainy mustard or spicy mustard, such as Gulden's
- Sliced Gruyere cheese, for melting
- Thinly sliced scallions, for garnish
Heat a soup pot over medium heat; add the butter and melt. When the butter foams, add the onions, leeks, shallots, garlic, bay leaf, thyme and salt and pepper. Partially cover and cook, stirring occasionally, until caramelized, about 35 minutes. Deglaze the pot with sherry, then add the Worcestershire and stock. Taste for seasoning when it comes to a bubble. Cool and store for a make-ahead meal.
Heat the soup and creme fraiche over medium heat until bubbly and thickened a bit. Toast the bread on the middle rack under the broiler; remove and top one side with the mustard and cheese. Return to the oven to melt the cheese.
Serve the soup in shallow bowls, topped with scallions and cheesy croutons.