Preheat your oven to 350°F (175°C) and line your baking sheets with parchment paper.

In a large bowl, cream together the softened unsalted butter, granulated sugar, and brown sugar until smooth and fluffy (about 3-5 minutes).

Beat in the eggs one at a time, followed by the vanilla extract, ensuring everything is well blended.

In a separate bowl, whisk together the baking soda, cornstarch, salt, all-purpose flour, and vanilla pudding mix until thoroughly combined.

Gradually add the dry mixture to the wet ingredients while stirring. Mix until just combined.

Gently fold in the colorful sprinkles to incorporate them throughout the dough.

Use a cookie scoop or tablespoons to place dough balls onto the prepared baking sheets, spacing them about 2 inches apart.

Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden.

Let them cool on the baking sheets for about 5 minutes before transferring to a wire rack.