Preheat oven to 350 degrees F (175 degrees C). Line 24 muffin cups with paper muffin liners.
Beat the pumpkin puree, white sugar, brown sugar, shortening, butter, milk, vegetable oil, and eggs together in a large bowl until smooth. Whisk the cake flour, dry buttermilk powder, cornstarch, pumpkin pie spice, baking powder, baking soda, and salt together in another bowl. Add the dry ingredients to the pumpkin mixture, stirring until mixed. Pour batter into the prepared muffin cups, filling each cup about 2/3 full.
Bake in the preheated until the center of the cupcakes spring back when touched, about 30 minutes. Cool in the pans for 10 minutes before removing to cool completely on a wire rack.