Cream the butter and sugars. Place the softened unsalted butter, granulated sugar, and packed light brown sugar in the bowl of a stand mixer. Beat on medium speed for approximately 2–3 minutes, or until the mixture is fluffy and thoroughly blended.

Incorporate the remaining wet ingredients. Add the instant vanilla pudding mix, room-temperature eggs, and vanilla extract to the creamed mixture. Continue beating on medium speed until the ingredients are fully incorporated and the mixture appears smooth.

Prepare the dough. In a separate small bowl, whisk the all-purpose flour with the baking soda. Reduce the mixer to low speed and gradually add the dry mixture to the butter mixture. Continue mixing just until a thick, cohesive cookie dough forms.

Add the mix-ins. Fold the white chocolate chips and festive sprinkles into the dough, distributing them as evenly as possible throughout the mixture.

Chill the dough. Remove the dough from the mixer and shape it into a ball. Enclose it securely in plastic wrap and refrigerate for a minimum of 1 hour. A longer chilling period may further firm the dough and allow the flavors to meld more fully.

Prepare the cookies for baking. Once the chilled dough feels firm, preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper. Using a 2-tablespoon cookie scoop, portion the dough into balls and arrange them approximately 2 inches apart on the prepared baking sheet. These cookies will spread only slightly during baking.

Bake. Place the baking sheet in the preheated oven and bake the cookies for 10 minutes, or until the lower edges become lightly golden. The centers will continue to set and firm as the cookies cool.

Cool and finish the remaining batches. Transfer the baked cookies to a wire cooling rack and allow them to cool completely. Continue portioning and baking the remaining dough in the same manner until all of it has been used.