Cream butter and sugar with an electric mixture until light and fluffy. Add eggs, one at time, and beat until well combined. Stir in vanilla or vanilla bean paste.
In a separate bowl, sift together flour, baking powder, and baking soda. Add the flour mixture to the creamed butter mixture. Mix until combined. You may need to finish mixing with wooden spoon by hand since the dough is very thick.
For easier handling, cover dough and chill in the refrigerator for at least 2 hours. Dough may be prepared up to three days in advance and stored in the refrigerator.
Once ready to bake, preheat oven to 375° F. Roll out half of the dough to ¼ inch thickness. Use a a mixture of equal parts powdered sugar and flour to roll out the cookie dough. This helps make the dough easy to roll out without making the cookies from becoming floury. The powdered sugar also adds a little sweetness.
Cut the cookies using shapes of your choice and sprinkle with colored sanding sugar, if desired. Bake on a cookie sheet lined with parchment paper in preheated oven for about 8-10 minutes, or until the edges are barely golden.
If decorating, let cool completely before frosting. Buttercream recipe is included.