Prepare the Pimento Cheese Spread: In a mixing bowl, combine the grated cheddar cheese, mayonnaise, and chopped pimentos. Stir until well mixed. Add salt and pepper to taste. For added flavor, you can mix in crispy bacon or pickled jalapeños.
Assemble the Sandwich: Lay out 4 slices of bread. Generously spread the pimento cheese mixture onto each slice of bread.
Finish the Sandwich: Top the cheese-covered slices with the remaining 4 slices of bread to complete the sandwiches.
Serve: Slice the sandwiches into halves or quarters and serve immediately. You can also toast the bread for a warm, crispy version of the sandwich.