Using a large bowl, beat the oil, vinegar, and house seasonings together. Add the mayonnaise, anchovy paste, and mustard, and stir until well blended. Fold in the shrimp, bell pepper, onion, parsley, and lemon juice. Place in refrigerator and marinate overnight.
Serve cold or at room temperature.
1 cup salt
1/4 cup black pepper
1/4 cup garlic powder
Mix ingredients together and store in an airtight container for up to 6 months