1. Preheat the oven to 390°F (200°C). Line a baking sheet with baking parchment and set aside. Chop the chocolate and walnuts and set aside.

2. Add flour, baking powder, brown sugar, and salt to a large bowl and mix to combine. Add the cold butter in small pieces and cut into pea-sized pieces with a pastry blender*. Mix the buttermilk with the eggs and vanilla extract, add to the bowl, and mix in. The dough will be very wet and sticky. Add the chopped chocolate and walnuts and fold in. Transfer the dough to a well-floured surface and flatten it to a thickness of about 1 inch (2,5cm). Use a large cookie cutter* (about 3 inches/8cm) and cut out rounds – place on the prepared baking sheet with some space in between. Collect scraps and cut out more scones.

3. Mix the egg and heavy cream and brush the scones with it. Sprinkle with some coarse brown sugar and bake for about 20-22 minutes until nicely browned. Take out of the oven and let cool down on a wire rack. Serve slightly warm.