In a medium bowl, combine flour, baking powder, salt, cinnamon, and nutmeg. In the bowl of an electric mixer, beat together the butter and sugars on medium-high speed until light and fluffy, 2-3 minutes. Blend in the pumpkin puree. Beat in the egg and vanilla until incorporated. With the mixer on low speed add in the flour mixture until just incorporated. Cover and chill the dough in the fridge for at least 1 hour.