In a large skillet, cook onion and garlic in hot butter and oil about 5 minutes or until golden. Add tomatoes and bay leaves. Bring the mixture to boiling. Reduce heat and cook, uncovered, for about 10 minutes or until most of the liquid in the skillet evaporates.
Stir in water, sugar, black pepper, chili powder, and salt. Bring mixture to boiling. Add the shrimp. Reduce the heat and cook, uncovered, over medium-low heat for about 3 minutes or until the shrimp is opaque, turning over after half the cooking time.
Remove from heat and discard the bay leaves. Stir the olives into the sauce.
Serve the jumbo shrimp hot with slices of crusty bread, if you like. Makes 4 or 5 appetizer servings, or 2 or 3 main-dish servings.