01 - Cook bacon in a skillet over medium heat until crisp. Transfer to paper towels to drain excess fat.
02 - In a small bowl, combine softened butter with 1 tablespoon of maple syrup until well incorporated.
03 - Evenly spread the maple butter mixture onto one side of each slice of sourdough bread.
04 - Heat a clean skillet or griddle over medium-low heat.
05 - Place one slice of bread, buttered-side down, onto the preheated skillet. Layer with cheddar cheese, 2 slices of bacon, a few thin apple slices (if using), and a light drizzle of the remaining maple syrup. Top with another slice of bread, buttered-side up.
06 - Grill each sandwich for 3 to 4 minutes per side, pressing gently with a spatula, until the bread is golden brown and the cheese is fully melted.
07 - Remove the grilled cheese sandwiches from the skillet, slice them in half, and serve immediately while warm.