In a medium sized bowl, use an electric mixer to beat the butter and sugar until light and fluffy (about 2-3 minutes).
¾ cup unsalted butter, 1 cup granulated sugar
Add the egg, and vanilla extract. Mix until combined.
1 large egg, 1½ tsp vanilla extract
Pour the flour, baking soda, and salt into the bowl and mix until everything is combined. It will seem crumbly at first but continue to mix until the dough forms.
2 cups all-purpose flour, ¾ tsp baking soda, ¼ tsp salt
Use a rubber spatula to gently mix in the sprinkles. Place the cookie dough in the fridge for at least 30 minutes to chill.
½ cup sprinkles
Once the cookies have chilled, preheat the oven to 350° F and prep a baking sheet with parchment paper.
Use a medium cookie scoop (1.5 tbsp) to scoop the cookies onto the baking sheet. Optional: roll the tops in extra sprinkles if wanted.
Bake the cookies for 9-11 minutes, or until the outer edges of the cookies are slightly browned, the middle should still look underdone.
Remove from the oven and allow them to cool on the pan for 5 minutes, and then transfer to a wire cooling rack to cool completely.