Add butter to a saucepan and heat at medium. Don't let it burn. Continually stir with a wooden spoon and remove from heat when butter particles start to brown, about 5-8 minutes. Set aside and allow to cool.
In the bowl of a stand mixer, add browned butter, shortening and sugar. Mix thoroughly until creamed together. Add egg and vanilla and mix thoroughly. Add sifted flour, baking powder and salt. Quickly mix until just combined, don't over mix. Add sprinkles and combine with a rubble spatula.
Using a medium cookie scoop, approximately 1.5 tablespoons, scoop dough balls and roll with your hands into a complete ball. Place onto a cookie sheet covered with a Silpat or parchment paper. Bake for about 10 to 12 minutes. Allow to cool on cooling racks.
Cookie Tip:
Store your cookies in an airtight container with a piece of bread. The bread will dry up and keep your cookies soft.
Notes
I modified the original sugar cookie base recipe from these Soft Sugar Cookies.