Begin by preheating your oven to 350°F (175°C) and lining a baking sheet with parchment paper to prevent sticking.
In a large mixing bowl, combine the softened butter, granulated sugar, and brown sugar. Using an electric mixer, cream the mixture on medium speed for about 2-3 minutes, or until it’s light, fluffy, and well combined.
Crack in the eggs, adding them one at a time. Ensure each egg is fully incorporated before adding the next. Follow with the pure vanilla extract and mix well to combine everything.
In a separate bowl, whisk together the all-purpose flour, baking soda, and fine sea salt until thoroughly blended. Gradually add this dry mixture to the wet ingredients, mixing on low speed just until no flour pockets remain—avoid over-mixing to keep your cookies tender.
Gently fold in the rainbow sprinkles and white chocolate chips using a spatula, ensuring they're evenly distributed throughout the dough without breaking the sprinkles.
Using a cookie scoop or a tablespoon, portion rounded balls of dough and place them on the prepared baking sheet, spacing them about 2 inches apart to allow for spreading.
For an extra pop of color, carefully press a few additional rainbow sprinkles on the top of each cookie before baking.
Bake the cookies in the preheated oven for 10-12 minutes, or until the edges just begin to turn golden brown while the centers remain soft and chewy.
Once baking is complete, remove the baking sheet from the oven. Allow the cookies to cool on the sheet for 5 minutes, then transfer them to a wire rack to cool completely.
Notes
For a festive touch, serve on a vibrant plate or stack in a jar with a ribbon.