2 lbs. shelled, deveined shrimp
3/4 c. olive oil
2 onions, quartered and sliced into thin rings
3 crushed cloves of garlic
1/2 tsp. chili powder
1/4 tsp. dry mustard
1 1/2 tsp. salt
1/2 tsp. black pepper
1/2 c. vinegar

Saute onions and garlic in 1/4 cup olive oil for ten minutes. Add shrimp and saute for 7 to 8 minutes, stirring a few times during cooking. Remove shrimp from pan with slotted spoon and set aside to cool while preparing sauce.

Mix remaining 1/2 cup olive oil together with all other ingredients. Add shrimp, being sure to coat all the shrimp with the marinade. Cover and refrigerate dish. Baste shrimp occasionally. Before serving, bring to room temperature.