- Preheat the oven to 170°C.
- Combine the butter and sugars in a stand mixer fitted with the whisk attachment. Beat together on medium speed until well combined and lightly coloured. Do not overmix.
- Add the eggs, one at a time, mixing well after each addition.
- Add the remaining ingredients and whisk on low speed until well combined.
- Line three baking trays with baking paper.
- Shape the cookie dough into 45g balls and place on the trays, spaced about 3cm apart to allow for spreading. Gently flatten them to about 1cm thick, then make a small dent in the centre of each cookie with your finger.
- Place a generous 1½ teaspoons of Nutella in each of the dents.
- Sprinkle each cookie with a little sea salt.
- Bake for 15 minutes, then transfer to a wire rack and leave to cool and crisp up before serving.
Adapted from Feasting by Amanda Ruben (Hardie Grant, £25)