Tomato Fish Casserole with Potato and Peas Puree

Wash the fish fillet, pat dry and cut into 4 portions. Preheat the oven to 200 degrees upper and lower heat (convection 180 degrees). Wash the tomatoes, cut off the stalks, cut the tomatoes into slices. Wash the spring onions and cut into strips. Halve the lemon and squeeze out. Place the fish fillet pieces in a baking dish. Drizzle with the lemon juice ,Season with salt and pepper . Scatter tomatoes, spring onions and grated cheese on top, put in the hot oven and bake on the middle rack for about 25 minutes. In the meantime, wash the potatoes, peel them, cut into small pieces and cook them in lightly salted water for 15 minutes, add the peas and cook for another 5 minutes. Then drain. Heat the milk and butter. Mash the drained potatoes and peas Add hot milk and stir in. Season the potato and pea puree with salt, pepper and nutmeg. Take the tomato and fish casserole out of the oven and allow to evaporate briefly. Serve hot with the puree.