Make the dough: Beat the butter and sugar together until light and fluffy (2-3 minutes). Add the eggs and vanilla and mix again for another 2-3 minutes. Stir in the pumpkin, sour cream, baking soda, baking powder, salt, and spices until smooth. Gradually mix in the flour until just combined.
Chill: Divide the dough in half, wrap in plastic wrap, and chill overnight (at least 8 hours). Chilling ensures the dough is easy to roll and helps the cookies hold their shape.
Roll and cut: Preheat the oven to 425°F. Roll one portion of dough on a lightly floured surface to 1/4-inch thickness. Cut out shapes with cookie cutters and place them on prepared baking sheets.
Bake: Bake the cookies for 10–12 minutes, until they are lightly golden. Cool for 5 minutes before transferring to wire racks to cool completely.
Frost: Beat the butter and cream cheese together until smooth, then add vanilla and powdered sugar. Mix until creamy. Frost cooled cookies and decorate as desired.