Step 1

In a large bowl, mix together the butter and sugar with a wooden spoon until combined and smooth. Do no beat, whip, whisk or otherwise aerate the mixture – you only want it combined.

Step 2

Add the milk and vanilla paste, and mix until combined.

Step 3

Sift the gluten free flour blend, xanthan gum and salt into the butter mixture. Add the chopped hazelnuts and chocolate, and mix everything together until combined and the add-ins are evenly distributed.As the dough comes together, you might find it easier to switch from a wooden spoon to kneading with your hands. The final dough shouldn't be sticky to the touch, but might be on the softer side.

Step 4

Shape the dough into a 5 inch/10 cm log (with a 2 inch/5 cm diameter), wrap in cling film or baking/greaseproof paper, and chill in the fridge for at least 1 - 2 hours or in the freezer for at least 30 - 60 minutes.When properly chilled, the dough should feel very firm/hard to the touch.

Step 5

Adjust the oven rack to the middle position, pre-heat the oven to 355 ºF (180 ºC) and line a large baking sheet with baking/greaseproof paper.

Step 6

Once chilled, unwrap the cookie dough log and roll it in the demarara sugar (optional). If the sugar doesn't stick, lightly brush the cookie dough with water or milk – this will help the sugar adhere to the log surface.

Step 7

Slice the log into 1/3 inch/1 cm slices. If any chunks of hazelnuts or chocolate break away during slicing, press them back in place.

Step 8

Transfer the cookies onto the lined baking sheet at least 1/2 inch/1.5 cm apart, and bake at 355 ºF (180 ºC) for 16 - 20 minutes or until golden brown around the edges.

Step 9

Cool on the baking sheet for about 10 minutes, then transfer onto a wire cooling rack to cool completely.

Step 10

Sprinkle with flaky sea salt (optional) and enjoy!

Step 11

Storage: The cookies keep well in a closed container in a cool dry place for 1 - 2 weeks.