Make a dough from flour, salt, oil, and water. Knead until it no longer sticks to your hands; add more flour if needed. Let it rest for at least 30 minutes.
Stir the sour cream until smooth and season with a little salt, black pepper, and nutmeg. Peel the onions, halve them, and slice thinly.
Roll out the dough thinly on a floured surface and place it on a baking tray or pizza stone. Spread the sour cream on top, add the onions, and sprinkle with bacon.
Bake in a preheated oven at at least 200°C for about 20 minutes.