Instructions

1. Preheat the oven to 180°C (350°F).
2. Line a baking tray with baking paper.
3. Cream the butter and sugar together until light and fluffy. You can do this with a bowl and wooden spoon, but it is easiest and quickest with a handheld electric beater, or with a stand mixer and flat paddle attachment, on medium speed.
4. Beat in the egg and vanilla extract.
5. Slowly beat in the flour, baking powder, salt, and oatmeal. At this stage, you should have a thick cookie dough.
6. Add the Nutella to the cookie dough and use a wooden spoon to lightly mix it through the cookie dough. You don’t want to fully incorporate the Nutella into the dough, otherwise you will not achieve a marbled look on the cookies. Also, the Nutella will continue to be worked into the dough when you roll them into cookies.
7. Pinch off a small piece of dough and roll it into the size of a large walnut. Place the balls of dough onto the baking tray, but space them apart generously as they will spread as they cook.
8. Gently flatten each ball of dough.
9. Bake for 12-15 minutes, or until the cookies are lightly golden.
10. Leave the cookies to rest on the hot baking tray for about 5 minutes to firm up before eating, or before removing them to a wire rack to cool completely.