These coffee biscuits are the perfect celebration of coffee. This recipe is made from an espresso and walnut shortbread sandwiched together with a coffee chocolate ganache, the ultimate duking delight.
In a bowl of an electric mixer fitted with a paddle attachment, add the butter and sugar. Beat at medium-high speed until light and fluffy, about 5 minutes.
First, add the whole egg to the creamed mixture with the motor running, and beat until combined. Scrape down the side of the bowl and beat again. Then add the egg yolk and vanilla then beat again.
Sift together the flour and salt and add this to the egg and sugar mixture at once. Mix on medium-low speed until just combined.
Add the chopped walnuts, and espresso granules to the biscuit mixture and mix until just combined. Remove the dough from the bowl, cover in plastic wrap, and refrigerate for 40 minutes.
To make the ganache, heat the cream in a small saucepan over medium heat until boiling. Remove from the heat and add the instant coffee, stir until dissolved. Pour the coffee cream over the chopped chocolate, stir until the chocolate is melted. Set aside to thicken.
Preheat the oven to 160°C (320°F) and line two large baking trays with parchment paper.
Remove the dough from the fridge and roll it out to ½ cm ( ¼ inch) thickness on a floured surface. Cut out the cookies using a cookie cutter.
Place the cookies onto a lined baking tray and bake in a preheated oven for 12 minutes or until light golden brown. Allow the cookies to cool on a cooling rack.
Once the ganache has thickened and is pipeable, add it to a piping bag fitted with a nozzle. Pipe a swirl of ganache onto half of the biscuits and top with the other half of the biscuits. Serve and enjoy!