Scoop heaped teaspoons of Nutella onto a lined tray, and freeze until solid. This usually takes 30-60 minutes!
Once the Nutella has frozen, make your cookie dough!
Preheat your oven to 190C/170C Fan!
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, 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.
As you scoop each cookie, flatten the dough slightly into a disc shape, and add a frozen lump of Nutella to the middle and then wrap the cookie dough around the Nutella fully so its covered!
They will be balls of cookie in the end!
Line 2-3 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 11-13 minutes, or until golden. The more you bake, the less gooey they will be!
Notes
The freezing of the Nutella is important so it's easier to make, and to keep the Nutella gooey!
You can make these chocolate flavoured by taking out 25g of the flour, and adding in 25g of cocoa powder!
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!
They aren't designed to spread that much, but if you want you can flatten them if you can, but the Nutella being frozen makes it harder. I leave them as is.