1-2 shallots, chopped or 1-2 tbsp. chopped onion
1/2 tbsp. chopped garlic (optional)
3 tbsp. tarragon vinegar
1/2 cup canned tomatoes
1 tbsp. butter
1 tbsp. flour
salt and pepper and cayenne pepper, to taste
1/2 tsp. each chopped parsley, tarragon and chervil

Put shallot, onion, garlic and vinegar in a wide saucepan and simmer until about half the volume of liquid remains.

Add tomatoes and bring to a boil. Cream butter and flour together until well mixed. Stir this into the sauce.

Bring to boil over low heat, stirring constantly.

Season to taste, adding herbs, garlic or onion powder, salt and pepper, as desired.