Sift the flour into a bowl. In another bowl, mix the water with the sugar and crumbled yeast. Make a well in the flour and pour the mixture into it. Let rise for 15 minutes. Add oil and ½ teaspoon salt and roughly mix everything with a mixing spoon, then knead into a smooth dough with your hands. Let rise for another 20-30 minutes. Knead again well, then roll out into a large rectangle on a floured worktop. Transfer to a parchment-lined baking sheet.
Season the sour cream with salt, pepper, paprika powder and chilli flakes, stir well and spread evenly on the dough. Cut the ham into fine strips and spread on top. Cut the mozzarella into slices and spread on top. Bake in a preheated oven until golden brown for approx. 20 minutes at 200 ° C top / bottom heat.