Thinly slice zucchini, peel and dice tomatoes, fry in a pan. Halve the salmon fillet crosswise, season with salt and pepper. Place four pieces in a greased dish. Spread half of the fried zucchini, tomatoes and cheese on top, cover with the remaining pieces of salmon and cover with flakes of butter.
Cook in a hot oven for approx. 35 minutes at 180 ° C top / bottom heat.
Meanwhile, boil the potatoes, peel them and toss them in rosemary. Serve the salmon with the remaining vegetables and potatoes.