
Preheat the oven to 350F. Add the softened butter, white sugar, and brown sugar to a bowl. Using a stand mixer or hand mixer, mix the butter and sugars for 2-3 minutes, until fully combined.
Add the egg and vanilla and mix until fully combined. Add the flour, baking soda, baking powder, and salt. Mix until just combined -- until no streaks of flour remain. Add the sprinkles and mix on low until they're distributed throughout the dough.
Use a large cookie scoop (about 1/4 cup) to scoop the dough. Transfer the dough balls onto a parchment lined baking sheet. Top each dough ball with a few extra sprinkles (optional). Bake for 7-9 minutes, until the edges are just set (it might still look slightly doughy in the centers, this is perfect).
If you are making smaller cookies, adjust the bake time down. Start checking the cookies at 5 minutes, and remove from the oven when the edges are set.
Remove from the oven and let them cool on the baking sheet for 5 minutes, then transfer to a cooling rack to cool completely. Enjoy!