Preheat your oven to 400°F (204°C). While the oven warms, line two baking sheets with parchment paper and set aside.

In a stand mixer fitted with a paddle attachment, beat together the cold butter, brown sugar, and granulated sugar on medium speed until the mixture is creamy, approximately 2-3 minutes.

Incorporate the room temperature egg and egg yolk into the mixture and mix well until fully combined.

Pour in the vanilla extract and mix until everything is nicely blended and smooth.

In a separate bowl, whisk together the all-purpose flour, cake flour, salt, baking powder, and baking soda.

With the stand mixer on low speed, slowly add the flour mixture to the wet ingredients until mostly combined, creating a crumbly dough.

Gently fold in the sprinkles, mini semi-sweet chocolate chips, and white chocolate chips using a spatula.

Using a 1/3 cup measure or your hands, shape the dough into 8 large balls (approximately 6 ounces each).

Place 4 cookie dough balls on each baking sheet, spacing them out evenly.

Bake for about 10-12 minutes until the edges are golden brown but the centers still look slightly underbaked.

Remove from the oven and allow the cookies to cool on the baking sheet for about 10 minutes before transferring them to a wire rack.