We start by seasoning the chicken breasts and cutting the onion into julienne strips. Then, in a large frying pan with a little oil, brown the breasts on both sides (in two batches better). We remove the breasts and, in the same oil, we fry the onion. The onion has to be lightly poached, but it does not have to become caramelized, and it is important to avoid burning.
With the onion ready, add the glass of water and the cheeses to the pan. If we want, we can substitute half a glass of water by means of white wine, or even add a splash of brandy and flambé the onion. Then, over medium heat, we stir and crumble the cheeses until the sauce takes shape.
Finally, we adjust the salt and pepper sauce and add the breasts. We let they impregnate Well of the cheese sauce and we serve with abundant bread, because this dish asks for a lot of dipping.