Marinated Shrimp in Avocado Halves

Thaw shrimp, if frozen; set aside. In a medium size bowl, combine vinegar, lemon juice, salt, mustard, and pepper; set aside.

In medium skillet, cook shrimp, half of the onion slices and garlic in 2 tablespoons hot oil over medium heat for 4-5 minutes or until shrimp is cooked. Stir occasionally. Remove onion and garlic with slotted spoon; discard.

Add shrimp and remaining oil to vinegar mixture, along with remaining onion. Cover; stir occasionally. Chill overnight.

To serve, lift shrimp and onion slices from marinade. Spoon into avocado halves.