Torta ricotta e uvetta (ricotta and sultana cake)

This is a beautiful traditional cake from Lazio region, easy to prepare and absolutely delicious. The main ingredient is supposed to be sheep ricotta, but since here in Australia is almost impossible to find such an ingredient, is it possible to substitute it with normal ricotta (full fat).

Here are the ingredients for this cake:

for the dough:
30 g potato flour
70 g flour
65 g butter
35 g sugar
1 egg yolk
lemon zest

for the filling:
350 g ricotta
100 g white yogurt (greek yogurt)
100 g sugar
lemon zest
2 eggs
150 g sultana

for the decoration cream
2 dl cream
2 table spoon lemon juice
4 sheets gelatine
lemon zest

Pre-heat the oven to 170 degrees.

Let's start preparing the dough, without using a mixer because doesn't need to be worked too much. Put the softened butter in the middle of the flours with the egg yolk and the lemon zest. Mix quickly and briefly, then wrap the dough in plastic film and let it rest in the fridge for at least an hour.

Leave the sultana for few minutes in warm water, in the meanshile mix the ricotta in a bowl with 80 g of sugar, the yogurt, the lemon zest and the egg yolks; add the sultana, well squeezed to remove the water. Whip the egg whites until stiff with the remaining 20 g of sugar, and fold in with the other ingredients.

Roll the dough wuntil very thin (2-3 mm), then loosely roll it around a rolling pin to help you transfer the dough without breaking it; butter a pie pan (about 22-24 cm diameter) and dust it with flour, then unroll the dough into it. Pour the filling and bake for 50-60 minutes.

Boil the cream with the lemon zest, then remove from the heat and add the gelatine sheets already softened for a few minutes in cold water and squeezed. Once the cream is almost at room temperature, add the lemon juice; pour onto the cake and leave in the fridge for a couple of hours.