Prepare pimento cheese by combining cheeses, garlic, Worcestershire sauce, mayonnaise, pimento, pickles and pickle juice in large mixing bowl.
Cut stem from mushroom and wipe away any debris with damp paper towel. Rub olive oil evenly over entire mushroom surface.
Sear lightly in hot iron skillet just to heat through the mushroom. Remove mushroom from the skillet.
Melt butter skillet. Spread 2 tablespoons of the pimento cheese mixture on one slice of bread.
Top with the mushroom and second piece of bread. Turn and grill until browned on each side in buttered skillet.
Serve warm.
NOTE: You will have enough pimento cheese to make about 12 sandwiches. The pimento cheese is especially good as an appetizer with Fogwood Spiced Tomato Jam and pita points.