Preheat the oven to 180C / 350F, and line two baking sheets with parchment paper.
In a mixing bowl, whisk butter and sugars until fluffy.
175 g butter, 100 g light brown sugar, 60 g caster sugar
Whisk in the egg and vanilla extract.
1 large egg, 1 teaspoon vanilla extract
Add the flour, baking soda and salt, and mix until combined.
250 g all purpose flour, ½ teaspoon baking soda, ¼ teaspoon salt
Now, fold in chocolate chunks and half of the crushed mini eggs using a spatula or wooden spoon.
60 g white chocolate, 100 g dark chocolate, 100 g mini chocolate eggs
Scoop about 2 tablespoons of the batter per cookie into the baking sheets (make sure you leave space between each one).
Sprinkle the remaining mini egg pieces on the tops of the cookies.
Bake for 10-15 mins, remove from the oven and leave to cool for 10-20 minutes before transferring to a wire rack.
Notes
Use a cookie scoop; It helps each cookie be the same size. If there are bigger and smaller cookies, the smaller ones brown faster than the larger ones.