Freeze your Creme Eggs until solid. This usually takes at least 60 minutes!
Preheat your oven to 220ºc/200ºfan
Beat together your butter and sugar until fluffy, and then add in your vanilla and egg and beat again until smooth.
Whisk together your flour, cocoa powder, salt, bicarbonate of soda and cornflour, and then add in to the other mix.
Add in the finely chopped chocolate and mix until combined.
Scoop your cookies with a cookie scoop to portion. I make 12 cookies, as I have 12 frozen Creme Eggs.
As you scoop each cookie, flatten the dough slightly, and add the frozen Creme Egg to the middle and make sure the cookie surrounds the Creme Egg fully!
They will be balls of cookie in the end
Line 2 LARGE trays with parchment paper - and add 6 cookies to each tray. Each cookie might spread a bit whilst baking, so you want room for them to grow!
Bake in the oven for 9-10 minutes, or until delicious. The more you bake, the less gooey they will be!
You can make these plain flavoured by taking out cocoa powder and adding in the same weight of plain flour!
These are best fresh so that they are still warm and gooey, but will last for 3-4 days once made - you can easily microwave them so that they are gooey inside again!
The higher heat is designed to 'shock' the cookie and make sure it doesn't spread too much and destroy the Creme Egg.
You can have a lower temp (190/170C fan) if you wish, and bake for a bit longer, but they will probably spread more.
They naturally have a harder outside, and a much softer inside, and then the creme egg!