In a small mixing bowl, STIR together onion and cheese; ADD mayo; STIR with fork until mixture just holds together.
STIR in pimentos and some of their liquid; SEASON with ground pepper.
Refrigerate, covered, until ready to use; may store up to a week. Sandwich works well if toasted in skillet or lightly broiled. May combine with other fillings such as a slice of lunch meat and sliced tomatoes
We use any available brand of diced pimentos, usually sold in a jar.
Per Serving (excluding unknown items): 430 Calories; 42g Fat (85.4% calories from fat); 15g Protein; 2g Carbohydrate; trace Dietary Fiber; 69mg Cholesterol; 510mg Sodium. Exchanges: 2 Lean Meat; 0 Vegetable; 4 1/2 Fat.