Reduce the Cider: In a small saucepan over medium heat, simmer 2 cups fresh apple cider for 20 to 25 minutes until reduced to exactly 1/2 cup of deep amber boiled cider syrup. Let cool to room temperature.

Whisk Dry Blend: In a large mixing bowl, whisk together the flour, cornstarch, dark brown sugar, baking powder, baking soda, cinnamon, nutmeg, and salt.

Whisk Wet Blend & Whip Whites: In a medium bowl, whisk the egg yolks, buttermilk, melted cooled butter, vanilla, and cooled cider reduction until smooth. In a clean, dry bowl, beat the egg whites with a hand mixer or whisk until stiff peaks form.

Combine Batter: Pour the yolk-buttermilk mixture into the dry ingredients and stir gently with a spatula just until barely combined (a few flour streaks are fine). Gently fold in the whipped egg whites in two batches until no large white streaks remain. Do not overmix.

Bake the Waffles: Preheat your Belgian waffle maker on medium-high heat. Brush lightly with melted butter or oil. Pour 1/2 to 2/3 cup of batter onto the hot grid. Close and bake for 4 to 5 minutes until deep golden-brown, crisp on the outside, and steam stops escaping. Transfer cooked waffles directly onto an oven wire rack set at 200°F (95°C) to keep them ultra-crispy while baking the rest.

Caramelize Apples & Serve: In a skillet over medium heat, melt 2 tablespoons butter. Add sliced apples, maple syrup, and cinnamon. Sauté for 5 minutes until tender and caramelized. Stack hot crispy waffles on plates, top with caramelized apples, whipped cinnamon butter, and warm pure maple syrup. Serve immediately!