4 slices artisan Italian bread
2 heads baby romaine lettuce, split lengthwise
1/4 cup crisply cooked bacon
1/4 cup thinly sliced red onion
1/4 cup Caesar dressing
Heat gas grill on medium-high or charcoal grill until coals are ash white.
Layer 2 slices cheese onto 2 slices bread; top with remaining bread slices. Spread outside of bread slices with butter. Place onto grill. Cook, turning once, 5-8 minutes or until golden brown. Cool slightly. Cut into 1-inch cubes.
Place halved romaine lettuce heads directly onto grill. Cook 2-3 minutes or until grill marks appear. Turn 90 degrees; cook 2-3 minutes or until grill marks appear.
Remove lettuce heads to serving plates. Top each with croutons, bacon, onion slices and dressing.
Serve with additional dressing, if desired.
Grilled cheese sandwiches can be made ahead and kept at room temperature up to 2 hours. Place onto cooling rack to keep bread crisp. If you prefer, you can cook sandwiches on stovetop in 10-inch nonstick skillet over medium heat.