Oil the springform slightly.
Prepare the yeast dough for the crust according to the instruction. Roll out the dough as thin as possible & cut out a cricle fitting in the springform (bottom & edge). Knead together the rest of the dough & roll out again for the top of the tart.
Put the dough in the springform (bottom & edge).
Preheat the oven to 160° C w/ fan.
Peel & trim & dice the potatoes.
Cook potatoes & rice in salted water until soft (about 10 - 15 min). Then drain the mess.
Grate the pecorino.
Mix ricotta, egg & pecorino. Add the drained potatoes & the rice. Add salt & pepper to taste.
Fill the mess into the springform & cover the mess w/ the dough for the top. Prick the top w/ a fork.
Let it bake for about 45 - 50 min.
After about 10 min of cooling open the springform & transfer the tart to a cooling rack or the serving plate.