2 Tbsp. olive oil
2 Tbsp. butter
1 medium onion, sliced
1 to 2 stalks celery, chopped
1 green pepper, sliced
1/2 lb. fresh mushrooms, sliced
3 large green olives, chopped
1 (6 oz.) can tomato paste, with 2 c. water*
2 Tbsp. parsley, snipped
1/2 to 1 tsp. salt
dash of pepper
1 bay leaf
1 tsp. dried oregano

*Or, 1 (12 ounce) tomato sauce and 1 cup water or tomato paste and whole tomatoes and little water.

Sauté onion, then add tomato paste, water, parsley, salt, pepper, bay leaf and oregano. Simmer 30 minutes; stir occasionally. Serve over pasta, rice or fish.