Ingredients

Step by step

1. Using the paddle attachment on a stand mixer, beat the butter and sugar together until light and fluffy (about 2-3 minutes). Add the egg, coffee and vanilla bean extract and beat until just combined, scraping down the sides of the bowl. Combine the flour, cocoa powder and bicarbonate of soda with a large pinch of salt. Add to the mixing bowl and briefly beat together until combined and it starts to form a dough. Transfer the bowl to the fridge and leave to chill for 1 hour.
2. Line two baking trays with baking paper. Pinch off pieces of the dough, about 2 teaspoons in size, and roll into balls. Roll the balls in the chopped hazelnuts. Place 1 inch apart on the prepared baking trays – you should have about 15 balls on each tray. Using your thumb or the end of a wooden spoon, press gently in the centre of each ball to create an indentation. Transfer the trays to the fridge for 15 minutes to firm up slightly.
3. Preheat the oven to 180°C, fan 160°C, gas 4. Transfer the trays to the oven and bake the biscuits for 8 minutes or until just set. Leave to cool and firm up slightly on the baking trays, then transfer to wire racks to cool completely.
4. For the ganache filling, transfer the chocolate to a large bowl. Heat the cream in a small saucepan until hot but not boiling, then pour over the chocolate, covering as much as possible, and leave to sit for a minute before adding the coffee and golden syrup and stirring everything together until smooth and combined. If the ganache seizes, whisk in a splash or two of freshly boiled water until smooth and glossy. Spoon into the centre of each thumbprint. Transfer to the fridge for 15 minutes before enjoying.