3 tablespoons butter
1/2 teaspoon dried tarragon
1/4 teaspoon nutmeg
1 large onion -- chopped
1/2 pound mushrooms -- trimmed and sliced
1/4 cup all-purpose white flour
3 1/2 cups beef broth
1 cup sour cream
1/2 cup half-and-half
1/2 cup whipping cream
salt and freshly ground pepper -- to taste
1 dash lemon juice
1 dash hot pepper sauce
Melt butter in a large heavy saucepan over medium heat. Add tarragon and nutmeg and cook for 1 minute. Add onions and cook until softened and translucent. Add mushrooms and cook until tender but nt soft. Add flour and cook, stirring for 3 to 4 minutes. Gradually stir in beef broth and heat, stirring, just until boiling. Reduce heat and stir in sour cream. Cook and stir until lumps dissolve. Add half-and-half and whipping cream. Season with salt, pepper, lemon juice, and hot pepper sauce. Heat gently, stirring frequently, until hot but not boiling.
