Preheat the waffle iron according to the manufacturer's instructions.
In a large mixing bowl, whisk together the eggs, buttermilk, pumpkin puree, oil, and vanilla until well combined.
2 large eggs, 1 ½ cups buttermilk, 1 cup pumpkin puree, ⅓ cup neutral oil, 1 teaspoon vanilla extract
Add the flour, cornstarch, brown sugar, baking powder, baking soda, pumpkin pie spice, and salt. Mix in just until combined.
2 cups all-purpose flour, 2 tablespoons cornstarch, ¼ cup light brown sugar, 1 tablespoon baking powder, ½ teaspoon baking soda, 2 teaspoons pumpkin pie spice, ½ teaspoon salt
Let the batter stand for about 5 minutes while the waffle iron finishes heating.
Lightly grease the waffle iron if necessary. Add the amount of batter recommended for your waffle maker.
Cook until the waffle is golden brown and crisp.
Serve with butter and maple syrup.
If you aren’t serving immediately, transfer the waffle directly a wire rack. Don't stack the waffles, or they'll steam and soften.
Notes
Oil: A neutral oil like canola oil or light olive oil works well in this recipe.
Pumpkin puree: Be sure to use pumpkin puree, not pumpkin pie mix or pumpkin pie filling. Pumpkin pie mix has sugar and spices already added to it.
Flour: To properly measure the flour, stir, lightly spoon into the measuring cup, and level.
Pumpkin pie spice: Pumpkin spice is a blend of warm spices like cinnamon and ginger. If you don't have this spice blend, you can make your own pumpkin pie spice blend with this recipe.