Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and line a couple of large baking trays with baking paper
To make the cookie dough, mix the egg and the Nutella together
Add the flour and mix until you can't see any flour anymore
Divide the dough into two pieces, then split one of the pieces into 10
Roll each of the small pieces into balls using your hands, then flatten into discs and place onto the baking paper
Spoon about 1 tsp of Nutella on top of each cookie dough disc
Then split the other piece of cookies dough into 10, roll into balls and flatten into discs as before, then place each disc over the first disc, covering the Nutella filling and pressing down around the edges to seal the filling in
Bake for 8-10 minutes, allow to cool on the tray for at least 5 minutes, then move to a cooling rack to cool fully
Store in an airtight container in a cool place and eat within 3 days
Video
Notes
Make sure your ingredients, particularly the egg, are at room temperature before you start baking.
You can use another brand of chocolate hazelnut spread to make this recipe if you prefer.
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50).
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.