In a heavy-bottomed pot, melt 6 tablespoons of unsalted butter and saute 2 diced shallots and 2 minced garlic over medium heat until the shallots become translucent.
Add in 2 diced carrots and stir for about 2 minutes. Add 24 ounces of sliced mushrooms and cook for an additional 4-5 minutes. Then stir in 1/2 tsp dried thyme and 1/4 tsp black pepper.
Turn the heat down to medium-low and add 1/2 cup + 2 Tbsp flour and cook for 2-3 minutes to cook out the raw flour taste.
Bring the heat to high and slowly pour 1 cup of dry sherry and keep stirring until the wine has evaporated. (About 3-4 minutes).
Pour in 6 cups of chicken broth and bring it to a boil. Now add in 3/4 cup heavy whipping cream and 2 tsp salt and cook for another 3 minutes to bring all the flavors out.
If you want to make this soup a little fancier, you can roll out 1 sheet of puff pastry cut a circular piece of thawed puff pastry and place it on top of an oven-safe soup bowl. Pinch the sides of the puff pastry around the soup bowl. Tip: place the oven-safe soup bowls upside down on top of the puff pastry as a guide before cutting it out.
Combine 1 egg and 2 tsp water and brush the tops and sides of the puff pastry. Bake for 15-20 minutes at 400 degrees Fahrenheit.