Sweet Pastry:

1. In the bowl of a stand mixer, sift the flour and icing sugar.
2. Add the butter and bring to crumbs. Add the orange and lemon zest and just mix through.
3. Mix the egg yolks and milk together. Add to pastry crumbs and mix until the dough forms. Form the dough into a round disc, cover in clingfilm and leave to rest in the fridge for at least 30 minutes.
4. Butter grease a 27cm/10.5-inch or slightly smaller springform tart pan.
5. Roll out the dough and arrange in the pan. Place in the fridge for 30 minutes before adding the filling.

Filling:

1. Preheat oven to 180C/350F.
2. Beat the ricotta and sugar with an electric whisk then add the egg yolks and beat until smooth and pale in colour.
3. Sift and add the potato starch and whisk until thickened.
4. Add the cinnamon until combined then add the mascarpone cheese and continue beating until smooth.
5. Add vanilla essence until combined and fold in the chocolate chips. Pour the filling into your prepared pastry case and gently flatten the surface. Cover the top with strips of pastry to form a lattice or diamond shape pattern.
6. Brush the pastry with a beaten egg and bake in preheated oven for about 1 hour or until pastry is golden.
7. Allow to cool before removing from pan, then serve dusted with icing sugar.
8. Enjoy!