Preheat oven to 350 degrees F. Line baking sheets with parchment paper; set aside
Cream the baking stick and sugar together until well combined.
Add in egg and vanilla. Cream together.
In another bowl, combine flour, baking powder and salt. Add the dry ingredients to the creamed mixture and combine well. It will be sticky; if you think it's too sticky, add a little more flour, 1 tsp at a time; too much flour will make dough tough.
Form dough into a disk and wrap in plastic wrap
Place in refrigerator for at least 1 hour
Sprinkle flour onto a flat surface, place the disk of dough on it and sprinkle a bit of flour on top.
Using a rolling pin, roll dough out to about 1/4 inch thickness. If sticky, lay plastic wrap on top and then roll over it.
Using a glass or cookie cutter, cut dough into desired cookie shapes. Place cookies onto parchment lined baking sheets.
Bake for 8 to 12 minutes (will depend on size and thickness of cookies) I find that gluten free flour doesn't brown as much as regular flour, but these will get lightly brown around the edges
Allow to cool completely before frosting and sprinkling with colored sugar
Prepare Frosting: Mix powdered sugar, baking stick, and vanilla until well combined. Add liquid 1 tsp at a time until desired consistency.
Prepare Colored Sugar: Place 3 tbsp of granulated sugar into a bowl. Add food coloring, 2 drops at a time and mix until desired color. Store in an air tight container.