Preheat your waffle maker to medium-high heat according to the manufacturer's directions.
Preheat the oven to 200°F (93°C). Place a wire cooling rack over a large baking sheet and set aside. This will keep the finished waffles warm and crisp while you cook the remaining batter.
In a large mixing bowl, whisk together the flour, baking powder, baking soda, cinnamon, pumpkin pie spice, ginger, and salt until evenly combined.
In a separate large bowl, beat the eggs vigorously for 1–2 minutes until frothy. You can use a handheld mixer, stand mixer with a whisk attachment, or a regular whisk.
Add the pumpkin puree, melted butter, brown sugar, maple syrup, vanilla extract, and whole milk to the eggs. Whisk until smooth and thoroughly combined.
Pour the dry ingredients into the pumpkin mixture. Mix on low speed or gently whisk just until combined. Do not overmix the batter; a few small lumps are perfectly fine.
Lightly grease the preheated waffle maker with nonstick cooking spray.
Add approximately 1/3 cup batter to each waffle well, adjusting the quantity for the size of your appliance.
Close the waffle maker and cook for approximately 5–6 minutes, or according to your waffle maker's instructions, until the Pumpkin Spice Waffles are crisp and golden brown.
Transfer cooked waffles to the prepared wire rack and keep them warm in the 200°F oven. Repeat with the remaining batter.
For the optional topping, place the pecans in a dry skillet over medium-low heat. Toast for 4–5 minutes, stirring frequently and watching carefully to prevent burning.
Once fragrant and lightly toasted, reduce the heat to low. Pour the maple syrup over the pecans and warm for approximately 1 minute. Remove from the heat.
Serve the waffles immediately with warm maple pecan syrup or your preferred toppings.