For the mushroom cheese baguette, skin the tomatoes and cut into fine cubes. Clean the mushrooms and also cut into fine cubes. Peel the onion and chop finely.
Heat the oil in a pan and sauté the onion until translucent. Mix the steamed onion, tomato and mushroom cubes. Cut the baguette rolls in half lengthwise.
Spread 25 g of cream cheese on each half, then spread the onion-tomato-mushroom mixture on top. Slice the mountain cheese very thinly and top the baguettes with it.
Bake in the preheated oven at 200 °C for about 12-15 minutes (until the cheese is well melted.)