This rich soup may have rustic origins, but it's equally at home on an elegant urban table.
- 2 tbsp. unsalted butter, plus extra butter for toast
- 1 medium onion, finely chopped
- 3 cups strong beef stock
- 1 1⁄4 cups Savoyard white wine, or other light, dry white wine
- 1 small carrot, peeled and thinly sliced
- 1 bay leaf
- 2 sprigs thyme
- 4 large slices French country bread
- 6 large egg yolks
- 1 1⁄4 cups crème fraîche
- Salt and freshly ground black pepper
Melt 2 tbsp. butter in a medium stockpot over medium heat. Add onions and cook until lightly browned, about 10 minutes. Add stock, wine, carrots, bay leaf, and thyme; bring to a simmer. Continue cooking for 15 minutes.
Toast bread slices on 1 side in preheated broiler. Generously butter and toast other side. Halve slices and set aside.
Strain stock and return to the same pot over low heat. Discard solids. In a medium mixing bowl, beat together egg yolks and crème fraîche. Whisk in 1 cup hot stock, then stir mixture back into pot. Season to taste with salt and pepper. Heat soup to serving temperature, but do not boil. Ladle into four bowls and top each serving with 2 halves of toast.