Preheat oven to 350F. In a large bowl, mix softened butter and sugars together until fully combined.
Add the egg and vanilla and mix. Add flour, baking soda, and salt - mix until no streaks of flour remain. Add sprinkles and slowly mix until combined.
Scoop or create dough balls [optional] onto baking sheet. Top cookies with a few extra sprinkles. Bake for 10-12 minutes until edges are set. Let cool before transferring from baking sheet. Enjoy!