Gino D'Acampo's ricotta tiramisu

Mix the ricotta cheese with the yogurt and sugar in a large bowl. Add the hazelnuts and vanilla extract and stir until well combined. Pour the cold coffee into a small bowl and mix in the cinnamon. Quickly dip half the sponge fingers in the coffee and then place in the base of a rectangular serving dish (30 x 22cm and at least 5cm deep). Spread half of the ricotta mixture on top. Repeat the process with the rest of the ingredients. Cover the dish with clingfilm and leave to rest in the fridge for 15 mins. Just before serving, dust the top with the cocoa powder.