PREPARE THE COOKIE DOUGH

1. In a medium mixing bowl, whisk together the gluten-free 1:1 flour, oats, cornstarch, baking powder, baking soda, and salt. Set aside.
2. In a large mixing bowl or the bowl of a stand mixer fitted with the paddle attachment, cream together the butter, light brown sugar, and granulated sugar on medium speed for 2–3 minutes, until light and fluffy.
3. Add the egg, egg yolk, and vanilla extract and mix until fully combined.
4. Add the dry ingredients and mix on low speed until just partially incorporated (~10 seconds).
5. Add the crushed Cadbury Mini Eggs and chocolate chips. Using a rubber spatula, fold the dough until no flour streaks remain and the mix-ins are evenly distributed.
6. Cover the bowl and chill in the refrigerator for 30-60 minutes.

BAKE THE COOKIES

1. Preheat the oven to 350°F and line a large baking sheet with parchment paper.
2. Scoop the dough into 3-tablespoon (70 g) portions and place 6 on the prepared baking sheet. Press additional crushed Cadbury Mini Eggs or chocolate chips on top if any spots appear bare.
3. Bake on the center rack for 10–13 minutes, until the edges are lightly golden and the centers are soft but no longer wet or shiny.
4. Immediately after removing the cookies from the oven, use a large round cookie cutter or the rim of a small bowl to gently swirl them into even, round shapes. The cookies will remain thick rather than spreading thin—if needed, you can lightly flatten them with the bottom of a glass or spatula after swirling.
5. Allow the cookies to cool on the pan for 10 minutes, then transfer to a wire rack to cool completely.
6. Repeat with the remaining dough (the recipe yields about 18 cookies).

Store cookies in an airtight container at room temperature for 3-4 days or up to 1 week in the refrigerator. Enjoy!