Mix butter with an electric mixer until very soft and creamy.
1 cup butter
Mix in sugar until light and fluffy.
1 ½ cups sugar
Add egg and vanilla. Mix well
2 teaspoons vanilla, 1 egg
Add flour, baking powder and salt. Mix until the dough is crumbly. The dough will look dry, but will come together when pressed.
3 ¼ cups flour, ½ teaspoon baking powder, ¼ teaspoon salt
Dump dough onto a flat surface. Divide into two piles. Working with one section at a time,form dough into a 10 inch log. The dough will begin to stick together when pressed. If it breaks apart, simply press back together.
Pour sprinkles onto a rimmed baking sheet. Roll logs into sprinkles.
½ cup colored sprinkles
Place each log on a sheet of plastic wrap. Pour additional sprinkles over each log. Wrap each log fully with plastic wrap. Use your hands over the plastic wrap to smooth sprinkles into logs.
Refrigerate for at least one hour.
Remove plastic wrap and cut into ½ inch slices. Place on a baking sheet lined with parchment paper or grease baking sheet lightly.
Bake in a preheated 375 degree oven for 12-14 minutes.
Let cookies cool slightly on baking sheet. Remove and continue cooling on baking rack.
Notes
Make certain butter is very soft, not melted, but soft enough to leave an indentation when lightly pressed.
This dough looks dry and crumbly after mixing. It will form together when molded with your hands.
Keep everything dry. If the sprinkles get wet, they will melt and run
Use a rimmed cookie sheet to help keep the sprinkles contained
Allow dough logs to fully chill before slicing and baking
Dough logs can be frozen for up to one month. Allow to thaw before slicing and baking.