Mince 2 garlic cloves. Finely dice 2 medium shallots and 2 medium carrots. Slice 24 ounces of baby bella or cremini mushrooms into 1/8- to 1/4-inch slices.

Heat a heavy-bottomed pot over medium heat. Melt 6 tablespoons of unsalted butter. Add the shallots, garlic, and carrots. Cook for a few minutes until the shallots are soft and translucent.

Add the sliced mushrooms and stir well. Cook for a few minutes until tender. Add 1/2 teaspoon dried thyme and 1/4 teaspoon black pepper. Stir well.

Sprinkle in 1/2 cup plus 2 tablespoons of all-purpose flour. Stir until the flour coats the vegetables and mushrooms. Cook briefly to remove the raw flour taste.

Pour in 1 cup of dry sherry. Simmer for 1 to 2 minutes. Slowly add 6 cups of chicken broth while stirring to prevent lumps. Bring the soup to a gentle simmer.

Stir in 3/4 cup of heavy whipping cream and 2 teaspoons of salt. Taste and adjust the salt as needed. Bring the soup back to a gentle simmer.

Simmer the soup for about 10 minutes over low heat. Stir occasionally. The mushrooms should be tender, and the soup should look creamy and smooth.

Puff pastry is optional. Keep 1 pound of thawed puff pastry cold until needed. Roll it gently on a lightly floured surface. Use an oven-safe bowl as a guide and cut pastry circles with 1/2 to 1 inch of extra pastry around the edges.

Whisk 1 egg with 1 tablespoon of water. Fill oven-safe bowls with hot soup and place the pastry over each bowl. Brush the tops with the egg wash.

Heat the oven to 400°F. Place the bowls on a baking sheet and bake for 15 to 20 minutes, until the pastry is puffed and golden brown. Let the bowls rest briefly before serving.

Skip the puff pastry and ladle the hot soup into bowls. Serve with crusty bread for dipping.