Soft and Chewy Funfetti Cookies

1 Preheat oven to 350°F and line baking sheets with parchment paper.
2 In a large bowl, cream together butter, brown sugar, and granulated sugar until smooth and fluffy, about 2 minutes.
3 Add egg, egg yolk, and vanilla. Mix until fully combined.
4 In a separate bowl, whisk together flour, baking soda, and salt.
5 Add dry ingredients to wet ingredients and mix until just combined.
6 Fold in sprinkles (and white chocolate chips if using).
7 Scoop dough into 2 tablespoon balls and place on baking sheet.
8 Chill for 20–30 minutes (optional but helps with thickness).
9 Bake for 9–11 minutes, until edges are set and centers look slightly underbaked.
10 Press extra sprinkles on top right after baking for that bright, bakery look.