This variation on a classic is topped with apple and bacon slices for the ultimate sweet and savory combination.
Preheat oven to 350 degrees. Place 4 slices bacon on a rimmed baking sheet (lined with parchment paper for easy cleanup); bake until crisp, 6 to 8 minutes per side. Drain on paper towels; tear each slice into quarters.
Place 4 thick slices whole-wheat sandwich bread on clean baking sheet. Top with sliced cheddar cheese, red apple, quartered, cored, and sliced crosswise, and bacon. Bake until cheese has melted, 10 to 12 minutes.