Sugar-free Cassata Siciliana

For the candied fruit: put the peels in a heavy-based pan and and just cover with water. Bring to a boil, drain and repeat twice more. Place the peel in iced water.

Combine the water and agave syrup in the same pan. Bring to a boil, add the cold peel, return to to a boil, then reduce the heat and simmer very gently, uncovered for 1 hour.

Remove from the heat, cover, and stand overnight.

Drain the peel in a sieve, shaking as much water off as possible. Place the peel on a wire rack and allow to dry at room temperature for 24 – 48 hours.

For the cake: heat the oven to 180°C (160° fan) 350°F gas 4. Grease a 25cm x 37cm|10" x 15" Swiss roll tin and line the base with non-stick baking paper.

In a medium bowl, whisk the egg whites, cream of tartar and salt, until stiff peaks form. Set aside.

In a separate bowl, beat the egg yolks, xylitol and lemon zest until light and fluffy. Sift in the flour, cornflour and baking powder, mixing to incorporate.

Fold in the egg whites, gently stirring until combined. Spread the mixture in the tin and smooth the top.

Bake for 12-13 minutes, until it just begins to pull away from the sides of the tin and springs back when lightly pressed. Cool for 5 minutes in the tin, then invert onto a wire rack, remove the paper and cool completely.

For the filling: put the ricotta cheese into a sieve and drain well.

In a small pan, heat the water and xylitol, stirring constantly until the xylitol has dissolved. Remove from the heat and cool slightly. Add half the liqueur, if using stirring to incorporate.

Stir the xylitol mixture into the ricotta. Add the sultanas, pistachio nuts and candied fruit.

To assemble: Line a 2 litre bowl with cling film. Cut a bowl size round out of the cooled sponge cake and place it in the base of the bowl.

Cut the remaining sponge cake into strips and fit the strips around the edges of the bowl. Drizzle the remaining liqueur over the sponge cake if using. Spoon the ricotta mixture over the cake, smoothing the top. Cover with foil or cling film and chill overnight.

Invert the cake onto a serving plate and gently peel away the cling film.