In a large mixing bowl, combine ½ cup of melted unsalted butter with ½ cup of granulated sugar and ½ cup of brown sugar. Mix until smooth and creamy, about 2 minutes.

Add one large egg and 1 teaspoon of vanilla extract, blending until fully incorporated.

In a separate bowl, whisk together 2 cups of all-purpose flour, ½ teaspoon of baking soda, ½ teaspoon of baking powder, and ¼ teaspoon of fine sea salt.

Gradually add this dry mixture into the wet ingredients while stirring gently until just combined.

Fold in ½ cup of Christmas sprinkles until evenly distributed throughout the dough.

Cover the bowl and chill in the refrigerator for 30 minutes.

Preheat your oven to 350°F (177°C) and line baking sheets with parchment paper.

After chilling, scoop the dough onto the baking sheets, spacing them about 3-4 inches apart.

Bake for 9-11 minutes, until edges are lightly golden and centers are set but soft.

Let them cool on the baking sheet for 5 minutes, then transfer to a wire rack.

Add extra sprinkles on top while still warm if desired.