If they aren't already frozen, freeze your mini Creme Eggs overnight.
Preheat your oven to 190C/170C Fan and line a 9x9inch square tin with parchment paper, and leave to the side for now.
In a larger bowl, melt the butter. Add in the two sugars, and whisk for about 2 minutes so the sugar starts to dissolve and the mixture is smooth. Add in the egg and the vanilla, and whisk again briefly until smooth.
In another bowl, add in the cocoa powder, plain flour, bicarbonate, salt, and cornflour. Whisk together until distributed evenly! Beat the two mixtures together.
Add in your chocolate, and the unwrapped frozen mini Creme Eggs (and as the mixture should be quite dry) combine it together with your hands or a spatula.
Press the mixture into the bottom of the tin and press in the handful of into the top for decoration. Bake the traybake in the oven for 18-20 minutes, until the top of the cookie bake looks ‘dry’ and a skewer comes out basically clean, bar a few crumbs.
Leave the cookie bake to cool for about 10 minutes, then leave to cool fully on a wire rack. Cut the bake into 4×4 for decent sizes, or 5×5 for smaller ones! Enjoy!
Notes
I used 4 of the mini Creme Egg Bags as each has 8 mini Creme Eggs in!
These cookie bars are best whens lightly gooey. The cookie bar will look dry when baked, and won't wobble, but should be slightly soft when still pressed. Once cooled they will be ideal!
These delicious beings will last in an airtight container for up to 5 days, but honestly, they’ll be eaten before then.
I’ve never personally tried this mix as an actual cookie, but if you try it out, let me know how you get on – I’d love to know if it worked!
It's VERY important to freeze the mini Creme Eggs before baking the cookie bars otherwise they might dissolve when baked.
I used Cadburys buttons for the other chocolate in the cookie bars.