Put the baking soda in the yoghurt to become effervescent. Then pour it into a wide bowl with 3 1/3 tbsp (50 ml) water, the egg, salt, flour.
Grate the cheese finely and add it to the other ingredients. Stir until you get a homogeneous, thick mixture. If it's too runny, add a little more flour and if it's too thick - add water.
Cut the bread into 1/2″ (1 cm) thick slices. Heat oil in a pan and fry the slices after dipping and rolling them well in the mixture.
In the same pan, braise thin slices of bacon just a bit and serve with the toast.