Put the flour in a bowl and press a depression in the middle. Dissolve yeast and sugar in 250 ml lukewarm water and pour into the hollow. Mix with some flour from the edge to a pre-dough. Cover and leave to rise in a warm place for about 30 minutes. Add 1/2 tsp salt and 2 tbsp oil to the pre-dough and knead for 5-10 minutes to a smooth dough. Form into 4 balls and let them rise again covered for about 30 minutes.
Mix ricotta and gorgonzola. Season vigorously with salt and pepper. Wash the rosemary, shake dry, pluck the needles from the twigs and chop. Peel and wash the potatoes and cut them into thin slices with a kitchen slicer
Roll out the dough balls on a floured work surface (approx. 22 cm Ø) and place 2 shelves each on a baking tray lined with baking paper. Spread each with 1/4 ricotta cream. Cover each with 1/4 of the potatoes, sprinkle with rosemary and drizzle 2 tbsp. olive oil. Bake the trays one after the other in a preheated oven (electric cooker: 250°C/ convection oven: 225 °C/ gas: level 5) for approx. 13 minutes
Waiting time approx. 1 hour