Mix milk, mineral water and eggs and about 1/4 teaspoon salt. Stir in flour. Leave to swell for about 10 minutes. Halve the bacon slices
Grease a small pan with a little oil. Fry 2-3 pieces of bacon briefly. Pour some batter on top and fry on each side for 1-2 minutes until golden brown. Bake another 7-9 pancakes. Roll them up and put them in a greased ovenproof dish
Coarsely grate the cheese, sprinkle over the pancakes. Bake in a hot oven (electric cooker: 225 °C/ convection oven: 200 °C/gas: level 4) for 3-4 minutes