Melt the chocolate and the butter together in a glass bowl set on top of a pan of boiling water or bain marie (make sure that the bowl does not touch the water). Stir occasionally. Once melted, remove the bowl from the pan and allow to cool a little.

In a small bowl, combine the flour, baking powder and salt and set aside.

Add the eggs to the bowl of a stand mixer fitted with a whisk attachment. Beat the eggs, slowly adding the muscovado sugar (making sure any lumps are broken up before you add it to the eggs). When all the sugar in incorporated, turn up the mixer to high and whisk for 6-8 minutes until the eggs have tripled in volume.

Reduce the mixer speed to low and add the cooled chocolate and butter mixture and the vanilla. Mix to combine, scraping down the sides once or twice.

Then add the flour mixture and until just combined.

The dough will be very soft. Refrigerate for 30 minutes (if you leave it in for longer it will take a little time to warm up before scooping and baking).

Preheat oven to 180F (350C).

Line 2 baking sheets with parchment paper.

Remove the dough from the fridge and scoop rounded tablespoons either with a small ice cream scoop or a spoon and place on the baking sheets, spaced about 5cm apart.

Top each ball/mound of dough with a light sprinkling of sea salt, pressing down gently so that they don’t fly off as you transfer the trays into the oven.

Bake for 8-10 minutes until the cookies have puffed up.

Allow to cool for a few minutes on the sheets before transferring to a rack to cool completely.

The cookies will keep for 3 days in an airtight container (if they last that long).