Start this recipe by lining the base of an 8 inch spring bottomed cake tin with non stick paper. Make a jam by cooking together the defrosted frozen strawberries and 120g caster sugar together for 10 minutes in a pan to form a jam. Allow to cool down. Meanwhile, crush the biscuits and mix with the chopped hazelnuts and melted butter. Press into the base of the cake tin. Spoon over half of the strawberry jam and spread out. Place in the fridge to chill. Meanwhile, prepare the filling. Place the gelatine sheets in a bowl of water to soften, then discard the water, add in the lemon juice and melt together in the microwave or bain marie. In an electric mixer fitted with a whisk attachment, whip the double cream to soft peaks and remove. Add the mascarpone, ricotta and 60g caster sugar to the bowl and whisk together till smooth. Stir in the remaining strawberry jam, gelatine mixture, followed by the whipped cream. Spoon the mixture over the prepared base and smooth out. Place in the fridge to chill and set for 2-3 hours or overnight. To serve, remove from the cake tin and place onto a serving plate. Decorate the edge with the chocolate fingers and tie with a red ribbon. Slice the strawberries and arrange decoratively on top.