1. Pulse first 7 ingredients and 1/3 cup mayonnaise in a food processor until blended but still chunky. Stir in bacon.
2. Spread about 1/3 cup cheese mixture on 6 bread slices; top with remaining 6 bread slices. Spread outside of sandwiches with a thin layer of mayonnaise. Cook sandwiches in a large nonstick skillet, in batches, over medium heat 2 minutes on each side or until golden brown.