Mix the mineral water, milk, eggs, salt, sugar and flour to form a runny batter. Let the dough rest for 15 minutes and stir again. Pour the dough onto a baking sheet lined with baking paper and bake in a preheated oven at 175 ° C top and bottom heat for about 25 minutes. If necessary, pierce the dough if it rises too high.
Then roll the dough up and down again using the parchment paper for the form. Cover the dough with cheese and ham and roll it up again piece by piece using the parchment paper, without rolling in the parchment paper. Then let the roll with the baking paper rest briefly in the residual heat in the oven for about 5 minutes.