Step 1

Preheat a waffle iron according to manufacturer's instructions.

Step 2

Combine the flour, baking powder, cinnamon, allspice, ginger, salt, and brown sugar in a mixing bowl. In a separate bowl, stir together the pumpkin, milk, and egg yolks. Whip the egg whites in a clean dry bowl until soft peaks form.

Step 3

Stir the flour mixture and 1/4 cup melted butter to the pumpkin mixture, stirring just to combine. Use a whisk or rubber spatula to fold 1/3 of the egg whites into the batter, stirring gently until incorporated. Fold in the remaining egg whites. Cook waffles according to manufacturer's instructions.

Step 4

To make the syrup, stir together the sugar, cornstarch, and cinnamon in a saucepan. Stir in the apple cider and lemon juice. Cook over medium heat until mixture begins to boil; boil until the syrup thickens. Remove from heat and stir in the 2 tablespoons of butter until melted. Serve warm.