1. In large bowl, whisk together flour, sugar, baking powder, baking soda and salt. In separate bowl, whisk buttermilk with egg. Whisk in butter; stir into flour mixture just until combined. Fold in bacon, apple and cheese. Let stand for 10 minutes.
2. Preheat waffle iron; cook waffles according to manufacturer’s instructions.
3. Make-ahead: Can be refrigerated for up to 3 days or frozen for up to 2 weeks. Reheat in toaster oven.
Tip: Add 1 tbsp. chopped fresh thyme or rosemary to waffles if desired.