Line a loaf tin with cling film.
Mix espresso with the coffee syrup in a shallow dish.
Soften the caramel ice cream at room temperature for 10–15 minutes.
Dip half the sponge fingers into the coffee mixture and arrange in the base of the tin.
Spread softened caramel ice cream evenly on top.
Sprinkle grated chocolate over the layer and freeze for 20 minutes.
Soften the coffee ice cream for 10–15 minutes.
Dip remaining sponge fingers and layer over the chocolate.
Spread caramel over the biscuits, then add coffee ice cream and level the top.
Cover and freeze for 2–3 hours until firm.
To serve, invert onto a plate, dust with cocoa powder, slice, and drizzle with chocolate sauce.