In a large mixing bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, and brown sugar. Set aside.
In a separate bowl, combine the pumpkin puree, milk, egg, and melted butter. Whisk until smooth.
Pour the wet ingredients into the dry ingredients. Gently stir until just combined. The batter should be slightly lumpy; overmixing can result in dense pancakes.
Place a non-stick skillet or griddle over medium heat and lightly grease it with butter or cooking spray.
Using a ladle or cookie scoop, pour about 3–4 tablespoons of batter onto the skillet for each pancake. Cook for 2–3 minutes until bubbles form on the surface, then flip and cook for another 2–3 minutes until golden brown.
Stack your warm pancakes, drizzle with maple syrup, and garnish with whipped cream and chopped nuts. Serve immediately for the best flavor and texture.