Combine butter and brown sugar in a sauté pan over medium heat. Whisk constantly until the butter is melted and the butter and sugar are combined. Add apples and bring to a simmer. Reduce heat to medium-low and simmer for 5 to 10 minutes until the apples are beginning to soften. Remove from heat and set aside to cool. Remove about 1/2 cup cooked apples and chop into smaller chunks to go into the waffle.

Preheat waffle iron according to manufacturer's directions.

In a medium bowl, whisk together the flour, baking soda, baking powder, salt, and brown sugar. In another bowl, whisk together the eggs and melted butter, and then add the buttermilk. Add the wet ingredients to the dry and stir until just combined. Fold in the crumbled bacon, cheddar cheese, and chopped apples. Allow the batter to rest for 5 minutes.

Pour the recommended amount of waffle batter onto the iron according to the manufacturer's recommendations. Close the waffle iron and cook until the waffle is golden on both sides and is easily removed from iron. Serve immediately or keep warm in a 200ºF oven until ready to serve. Serve topped with the remaining apple slices.