In a large bowl, cream together the softened butter and the sugar. Once smooth, add the eggs, vanilla and combine well.
Add the flour, salt and baking powder butter mixture and mix until the dough is smooth and flour is fully incorporated.
Split the dough in half (or in third if making three stripes) and color half the dough with a few drops of food coloring.
Cover each color separately with plastic wrap and chill in the refrigerator for 1 hour up to overnight.
When ready to roll, lightly flour surface, roll out each ball of dough separately to about 1/4 inch thickness.
Roll the lighter color dough around the rolling pin and transfer it on top of the other layer of dough.
Trim the edges and then start gently start rolling your dough to form the pinwheel.
Spill out some sprinkles onto the counter, brush the outside of the dough ‘log’ with a bit of water and roll it in the sprinkles. Chill the dough in plastic wrap for 10 to 20 minutes until firm enough to cut.
Slice the dough into rounds to your desired thickness then bake at 350 F for approximately 8-10 minutes.