Cream together butter and sugar for at least 2 minutes. Add eggs and vanilla and continue mixing.
In a second bowl, whisk together dry cookie ingredients.
Gradually pour dry ingredients into bowl of wet ingredients, mixing as you add, until everything is well combined.
Divide dough in half, placing each half in its own mixing bowl.
Mix red food coloring into one bowl of dough, until the dough is bright red.
Mix pink food coloring into the other bowl of dough, until the dough is a rich pink color.
Make the Pinwheel
Cut four sheets of parchment paper into 13" x 11" rectangles.
Place one sheet of parchment paper on the counter. Put the red ball of cookie dough on the center of the parchment paper and cover with a second sheet of parchment paper.
Use a rolling pin to roll the dough out to a 11" x 9" sheet that is about 1⁄4 inches thick.
Transfer the dough (still in parchment paper) to a cookie sheet.
Repeat this process for the pink cookie dough, then place both cookie sheets in the fridge to chill for at least 10 minutes.
Take the dough out of the fridge and remove the top layer of parchment paper from each sheet of cookie dough. Lightly sprinkle water on top of each sheet of dough.
Place one layer on top of the other layer, so that the sides without parchment paper touch. Press together.
Trim the dough so that all four sides are straight and you have an even rectangle shape.
Remove the top sheet of parchment paper and begin rolling the dough into a log shape.
Decorate, Slice, and Bake
Pour sprinkles onto a large platter or a sheet of parchment paper. Place the dough log in the sprinkles and roll to coat all sides. Press sprinkles into the dough to make sure they stay in place.
Chill the dough log in the fridge while you preheat the oven to 325 degrees.
Line baking sheets with parchment paper or silicone baking mats. Cut the dough log into 1/4" wide slices.
Place the slices on your prepared baking sheet. Bake for 10-15 minutes at 325°F.
Remove from oven and allow to cool slightly on the cookie sheets, the transfer cookies to a wire rack to finish cooling.
Notes
Nutrition values are an estimate only and may vary based on ingredients used and the size of cookies.