Ingredients
Method
Step-by-Step
- Heat the oven to 350°F (175°C) and line baking sheets with parchment paper. Set the prepared sheets aside while you mix the dough.
- Beat the softened butter and granulated sugar for 2–3 minutes, until the mixture looks light and creamy. Scrape down the sides of the bowl so the butter is evenly incorporated.
- Beat in the egg and vanilla extract until fully combined. The mixture may look slightly soft, but it should be smooth before the dry ingredients are added.
- In a separate bowl, whisk together the all-purpose flour, baking powder, and fine salt. This distributes the leavening and salt evenly through the flour.
- Gradually add the dry ingredients to the butter mixture, mixing just until no dry flour remains. Stop promptly to avoid making the cookies tough.
- Gently fold in the rainbow jimmies with a spatula. Use a light touch so the sprinkles stay whole and their colors do not streak through the dough.
- Cover the dough and chill it for about 30 minutes. Chilling firms the butter and helps the cookies keep their shape instead of spreading too much.
- Scoop tablespoon-sized portions, roll them into balls, and place them about 2 inches apart on the parchment-lined baking sheets. Press the tops lightly and add extra sprinkles if desired.
- Bake for 10–12 minutes per tray, until the edges are set and just lightly golden. The centers should still look soft because they will continue to firm while cooling.
- Cool the cookies on the baking sheet for 5 minutes, then transfer them to a wire rack. Let them cool fully before stacking or storing.
Notes
Use jimmies rather than nonpareils inside the dough because jimmies are less likely to bleed color. Do not overbake; the centers should look slightly underdone when the cookies come out. Store in an airtight container at room temperature for up to 5 days. Refrigerate unbaked dough for up to 3 days or freeze portioned dough balls for about 2 months.