In a medium bowl, whisk together flour, baking powder, baking soda and salt.
In a large bowl, cream together butter, sugar and vanilla until fluffy.
pumpkin puree or unsweetened applesauce
Gradually add dry ingredients, alternating with sour cream until well combined.
Transfer dough to smaller bowl and cover with plastic wrap.
Chill for at least 2 hours or overnight.
Preheat oven to 350 degrees F.
Line baking sheets with parchment paper or silicone mat.
Knead dough about ¼ of the dough at a time with a small amount of flour just until dough is not sticky.
Roll out onto floured surface about ⅛ - ¼ inch thick
Cut with cookie cutter and place on prepared baking sheet.
Bake for 10-12 minutes or until cookies are lightly brown.
Cool completely and frost as desired.