Fry bacon in a large skillet over medium heat until crisp.
Remove bacon to paper towels to drain.
Wipe out the pan.
Spread bread slices with honey mustard; layer four slices with Monterey jack, apple slices, bacon and gouda.
Top with remaining bread slices mustard side down.
Spread the outsides of sandwiches with butter.
Toast one sandwich, covered, in the same skillet over medium heat for 2-3 minutes or until the side is golden brown.
Flip sandwich; cook, uncovered, 2-4 minutes longer or until bread is lightly golden brown and cheeses are melted.
Repeat step with remaining sandwiches.