Crumble the fresh yeast in a cup and add the salt. Stir until the yeast has become liquid (the yeast reacts to the salt - it is not necessary to add water). Add to the flour with the mineral water at room temperature and the grated cheese, ham cubes and fried onions. Knead all ingredients into a yeast dough until it comes off the edge of the bowl, adding either a little flour or mineral water if necessary. Cover the bowl with a cloth and let the dough rise in the warm oven for about 10 minutes. Then take out the bowl and heat the oven to 200 ° C.
Shape the dough into a round loaf on a floured surface and place on a prepared baking sheet. Place in the hot oven (middle rack) and bake for 50 minutes. Then do the knock test and let cool on a grid.