Preheat oven to 350 degrees. Spray a cupcake tin with non-stick spray.

Combine flour, baking soda, salt, baking powder and pumpkin pie spice together in a bowl.

In the bowl of a stand mixer with the paddle attached, beat granulated sugar and butter together until fluffy. Beat in eggs one at a time. Scraping down the sides of the pan after adding each egg. Slowly beat in the dry ingredients. Fold in the pumpkin puree.

Fill in each cupcake mold 2/3 of the way full. Bake in preheated oven 15 -20 minutes or until a toothpick inserted comes out clean. Remove cupcakes from oven. Allow to cool for several minutes in cupcake tin, then transfer to a parchment paper lined cooling rack. Cool completely.

While cupcakes are cooling, heat butter over medium heat. As butter melts, it will foam slightly. Continue to cook until you notice little brown bits forming at the bottom of the pan. Stir the butter or shake the pan and continue cooking until the butter is a tan color and has a nutty aroma. Remove from heat and set it on a cool surface because it will continue to cook in the pan. Allow butter to cool completely.

Once cooled, place butter in a bowl with 2 1/2 cups powdered sugar and use a mixer to cream together. Add in remaining Beat in vanilla extract. Beat in maple syrup. Beat in 2 tablespoons of milk. The frosting will be thick but spreadable. Add remaining milk if frosting is too thick. Frost cupcakes and serve.