Sift together the flour, baking powder, baking soda, salt, pumpkin pie spice, and cinnamon into a bowl. Set aside.
In a separate bowl, whisk together the pumpkin puree, brown sugar, milk, oil, and egg until combined.
Add the dry ingredients to the wet batter and mix just until combined. Do NOT overmix the pancake batter.
Heat a large skillet or griddle on medium heat. Once hot, add butter and let it melt and swirl it around to coat the entire skillet. (Be sure to coat the skillet with butter, to avoid the pancakes from sticking to the skillet.)
Once hot, use a 1/3 cup measuring cup to scoop the pancake batter and pour it onto the skillet. Pour slowly, creating round pancakes, careful not to put too many pancakes at once. (You want to leave space in between each pancake for easier flipping.)
Cook the pancakes for about 3-4 minutes, until the edges have set and the center of the batter begins to form bubbles.
With a spatula, carefully flip the pancakes and cook until the other side and cook for another 2-3 minutes, until the bottoms are golden brown and pancakes are fully cooked through.
Add more butter or baking spray and repeat with the remaining batter. (As you cook the rest of the pancakes, cover the cooked pancakes to keep warm, or add to a warm oven.)
Serve with desired sides immediately, while cakes are still warm.