Whisk the flour, dark brown sugar, baking powder, pumpkin pie spice and salt together in a large mixing bowl to aerate them. In a separate bowl, whisk the buttermilk, eggs, pumpkin puree and extract together until smooth. Pour the wet mixture into the big bowl of dry ingredients and whisk it all together just until it's a smooth batter. At this point it can be covered and refrigerated up to overnight if desired. Let the batter rest for at least 30 minutes before cooking.

When you're ready to cook the waffles, preheat your waffle iron. Be sure to read the instructions on your particular iron for best results. Spray the iron well with cooking spray and scoop enough of the batter in to the iron to just cover the bottom. Close the iron and cook the waffle for about 5 minutes. Remove it when it is done and repeat until the batter is gone. With the size of my iron, I yielded 4 waffles.

While the waffle cooks, quickly prepare the cream cheese topping. Combine the cream cheese, milk, maple syrup and pumpkin pie spice in a bowl. Use a hand mixer to whip it all together well. Serve each waffle immediately when it's done cooking with a generous dollop of the cream cheese topping and a sprinkle of chopped walnuts! The waffles can even be made ahead and frozen! The cream cheese topping can also be made ahead and sealed in a container in the refrigerator.