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

Whisk together the all-purpose flour, baking powder, baking soda, and salt in a medium bowl.

In a large bowl, cream together the softened unsalted butter, granulated sugar, and brown sugar until light and fluffy.

Add the cold egg and vanilla extract, mixing on low speed until combined.

Gradually add the dry mixture to the wet mixture, stirring until just combined.

Fold in the pastel M&M's and white chocolate chips using a spatula.

Scoop the dough into mounds of 1½ to 2½ tablespoons and arrange them on the prepared baking sheets.

Press the tops into pastel sprinkles for a festive look.

Bake for 8 to 11 minutes until edges are set but centers look slightly underbaked.

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