Preheat your oven to 350° and grease a 9x13" baking pan with butter

In a large mixing bowl, combine your butter and sugar and beat until light and fluffy (2-3 minutes)

Now mix your eggs and vanilla extract

Then mix in your flour, baking powder, and salt until you have a thick dough (dough might seems crumbly at first, keep mixing)

Separate your dough into three bowls, add a few drops of food coloring to color each one a different color, and mix well

Break off colored pieces of your cookie dough and press into the bottom of your baking pan

Bake for 20 to 25 minutes and let cool

Frost your bars with your vanilla frosting and top with festive sprinkles