Irish Cream Sugar Cookies

Cream together butter and sugar until fluffy. Beat in vanilla and egg yolk until combined, then beat in egg; beat until smooth. Pour in Irish cream, and beat until incorporated. Sift together flour, salt, and baking powder. Stir into butter mixture until evenly mixed. Form into a flattened ball, wrap well with plastic wrap, and refrigerate 2 hours to overnight. Preheat oven to 350 degrees F (175 degrees C). Line two baking sheets with parchment paper. Roll dough out to 1/4 inch thickness on a floured work surface. Cut into shapes using cookie cutters and place onto prepared baking sheets. Bake in preheated oven until golden brown around the edges, 6 to 8 minutes. Cool on a wire rack until they reach room temperature.