Rainbow Square Butter Cookies Recipe

These rainbow cookies look amazing when finished. You can easily make these with just a little precision but the final result is beautiful. They are perfect to serve as a vibrant, yummy dessert.
Ingredients
2 cups cake flour(280g)
8 tbsp butter(110g)
1 egg
1 1/3 cups confectioners sugar
1/2 tsp salt
a little bit of vanilla extract
food coloring
a scale