In a medium bowl beat for approximately 2 minutes ¼ cup + 1 tablespoon of Nutella and the egg.
Add the sifted flour gradually and mix with a spatula or wooden spoon. Form into a ball, wrap in plastic and refrigerate for 30 minutes. The dough will be soft but will hold together, if too soft add a little more flour if too dry add a little more Nutella.
Pre-heat oven to 350°F (180°C), line a cookie sheet with parchment paper.
Remove the dough from the fridge and roll into 10-12 balls, with finger or bottom of wooden spoon press down the centre of each ball, making a deep well in the middle - deep but not too wide.
Fill a pastry bag with the remaining Nutella.
Depending on how you like your cookies you can either fill them with Nutella before baking or after (we like them both ways so I usually do half and half).
Bake for approximately 10-15 minutes, cookies will be a little soft but will firm up while cooling. Cool completely before filling unfilled cookies with Nutella. Sprinkle with chopped nuts if desired. Enjoy!
Notes
The dough can be made with either a mixer or a food processor, just be sure not to over mix the dough, just enough to bring it together then move to a flat surface to form into a compact dough ball.The cookies should be stored in an airtight container, they will keep at room temperature for up to 4-5 days. They can also be frozen, place in a freezer container, it is probably best to top them with the Nutella before serving. They will keep for up to three months in the freezer.