1. If you plan to bake some cookies right away, preheat your oven to 180°C (350°F) and line a baking sheet with parchment paper. If you are using a fan oven, or your oven runs hot preheat to 160°C (330°F)
2. In a large mixing bowl, beat together the softened 100g butter, 90g brown sugar, and 80g granulated sugar with an electric mixer until light and fluffy (about 2-3 minutes).
3. Beat in the 1 large egg and 1 tsp vanilla extract until well combined.
4. In a separate bowl, whisk together the 250g plain flour, 1 tablespoon cornflour, 1 tsp baking powder, 1 tsp bicarbonate of soda, and 1 tsp salt.
5. Gradually add the dry ingredients to the wet mixture, stirring until well combined. Avoid overmixing.
6. Gently fold in the 200g chopped mini eggs and 100g chocolate chips until evenly distributed.

Freezing the cookie dough

1. Use a cookie scoop or spoon to portion out the cookie dough into balls (about 1.5 inches in diameter).
2. Place the cookie balls on a baking sheet lined with parchment paper, making sure they don’t touch each other.
3. Freeze the cookie balls on the baking sheet for about 1-2 hours, or until completely solid. Once frozen, transfer the cookie balls to a freezer-safe bag or airtight container. Label and date the bags for future reference.

Baking the frozen cookie dough

1. When you’re ready to bake, preheat your oven to 180°C (350°F).
2. Line a baking sheet with parchment paper.
3. Remove the desired number of cookie dough balls from the freezer. You can bake them directly from frozen—there's no need to thaw them first.
4. If desired, gently press a few 75g whole mini eggs into the top of each frozen cookie.
5. Bake for 12-15 minutes, or until the edges are lightly golden and the centers are set. You may need to add a few extra minutes to the baking time since the dough is frozen.
6. Allow the cookies to cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.