I lived in Germany for many years and found this to be an excellent recipe for for "Hunter's Sauce:"

Ingredients:
2 Tbsp. minced onion or shallots
2 Tbsp. butter
1 cup sliced mushrooms
1/2 cup dry white wine
1/2 cup tomato sauce or puree
1 cup brown sauce (see below)
1 tsp. chopped parsley

Preparation:
Saute the onions in 2 Tbsp. butter. Stir in the sliced mushrooms and saute gently for about 2 minutes. Add the white wine. Simmer until mixture is reduced by half. Add tomato sauce and brown sauce and cook for 5 minutes. Season to taste and add 1 tsp. chopped parsley.

Quick Brown Sauce
1/2 clove garlic
2 Tbsp. butter
2 Tbsp. flour
1 cup beef bouillon
Rub pan with 1/2 clove garlic. Melt 2 Tbsp. butter. Stir in the flour until blended. Add 1 cup beef bouillon. Permit the gravy to reach the boiling point. Stir constantly. Season as required with: salt and pepper, dry sherry or worcestershire sauce, lemon juice, catsup or chili sauce, or dried herbs.