01 - Whisk together flour, sugar, baking powder, baking soda, and salt in a large bowl. In a separate bowl, combine milk, eggs, melted butter, and vanilla extract. Pour wet ingredients into dry and mix until just combined—avoid overmixing for tender waffles.
02 - Preheat waffle iron and lightly grease. Cook waffles according to manufacturer's instructions until golden brown and crisp. Prepare 8 waffles total to serve as buns for 4 burgers. Keep warm until assembly.
03 - Preheat oven to 400°F. Arrange bacon slices on a foil-lined baking sheet. Bake for 12–15 minutes, then brush both sides generously with maple syrup. Return to oven for 3–4 minutes until bacon is caramelized and crispy. Cool slightly and halve each slice.
04 - Divide ground beef into 4 equal portions and shape into patties slightly larger than your waffles. Season both sides generously with salt and black pepper.
05 - Heat a skillet or grill pan over medium-high heat. Cook patties for 3–4 minutes per side for medium doneness. Place a cheddar slice on each patty during the final minute of cooking to melt.
06 - Whisk together mayonnaise, maple syrup, Dijon mustard, and a pinch of salt in a small bowl until smooth and fully incorporated.
07 - Butter one side of each waffle. Place in a skillet over medium heat and toast until golden brown and lightly crisped.
08 - Spread maple aioli on a toasted waffle. Layer with arugula, cheese-topped burger patty, maple bacon halves, and red onion slices. Top with a second waffle. Repeat for remaining servings and serve immediately.