Mix the Dry Ingredients - In a large bowl, whisk together the flour, brown sugar, pumpkin pie spice, baking powder, baking soda, and salt.
Mix the Wet Ingredients - In a large bowl, whisk together the eggs, buttermilk, pumpkin puree, milk, melted butter, and vanilla.
Make the Waffle Batter - Gently fold the wet ingredients into the dry ingredients until just moistened. Do not overmix the batter.
Cook the Waffles - Preheat the waffle iron over medium-high heat or to the desired browning level. Lightly grease with cooking spray. Add about ⅓ cups of batter to each section, adding more as needed depending on the waffle iron size. Close and cook until golden brown and crisp, about 5 to 7 minutes, or according to the manufacturer's instructions.
To Serve - Serve the waffles with desired toppings like butter and maple syrup.
Notes
Homemade Pumpkin Pie Spice: Combine 4 teaspoons cinnamon, 1 teaspoon ginger, ½ teaspoon nutmeg, ¼ teaspoon allspice, and ¼ teaspoon cloves.
Make it Gluten-Free: Use 1:1 gluten-free baking flour like Bob's Red Mill instead of all-purpose flour.
Keeping Waffles Warm:Heat the oven to 200ºF (93ºC). Place cooked waffles on a wire rack sitting in a sheet pan. Keep them warm in the oven for no more than 20 minutes so they do not dry out.
Storing: Cool and store in an airtight container in the refrigerator for up to 5 days. Wrap and freeze for up to 2 months.
Reheating Frozen Waffles:Microwave pancakes in a single layer for 30 to 60 seconds until hot. For crispy waffles, microwave to defrost for 30 to 45 seconds, then toast until crispy.