Preheat oven to 350°F (177°C). Place the oven rack in the center position and line a 12-cup muffin tin with cupcake liners.

In a small bowl, whisk together the gluten free 1-to-1 flour, baking soda, baking powder, and salt. Set aside.

In a large mixing bowl, use an electric mixer on medium-high speed to cream the room-temperature unsalted butter and granulated sugar until light and fluffy, about 2–3 minutes.

Add the eggs one at a time, beating well after each addition until fully incorporated. Then add the milk, plain Greek yogurt, and vanilla extract and mix on medium speed until smooth.

Reduce the mixer to low speed and add the dry ingredients. Mix just until the flour mixture is incorporated and no large streaks remain; do not overmix. Scrape the bowl as needed.

Let the batter rest for 20 minutes (this helps hydrate the gluten-free flour).

Using a spatula, gently fold the 1/4 cup rainbow sprinkles into the batter until just combined, being careful not to overmix.

Divide the batter evenly among the lined muffin cups, filling each about two-thirds full. Bake on the center rack for 18–22 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.

Remove the cupcakes from the oven and let them cool in the pan for 10 minutes. Transfer the cupcakes to a wire rack and cool completely before decorating.

Once completely cooled, frost with Vanilla Frosting or Chocolate Frosting and decorate with additional sprinkles as desired.