Preheat the oven to 350°F (175°C).

In a large mixing bowl, combine the pumpkin puree, brown sugar, granulated sugar, melted butter, and the egg.

In another bowl, whisk together the flour, baking powder, cinnamon, nutmeg, and salt.

Gradually fold the dry ingredients into the wet mixture until just combined.

Spoon the batter into greased muffin tins or silicone molds, filling each about two-thirds full.

Bake in the preheated oven for 20-25 minutes or until a toothpick comes out clean.

Remove from the oven and let cool for a few minutes before transferring to a wire rack.

Decorate with icing, sprinkles, or edible decorations as desired.