Soak bread in water. Peel and finely chop the onion. Knead minced, squeezed bread, onion, salt, pepper, mustard, paprika and egg. Form small balls from the minced mass. Heat oil in a pan and fry meatballs for 6-8 minutes at medium heat, turning them over.
Meanwhile, cook the rice in boiling salted water according to the instructions on the packet. In the meantime melt fat in a pot. Dust with flour, sweat on, deglaze with broth and cream, bring to the boil while stirring.
Stir in cream cheese. Season to taste with salt, pepper and sugar. Grate cheese. Pour corn into a sieve and drain. Wash tomatoes and cut into slices. Mix rice, meatballs, peas, corn and tomatoes, put into a greased casserole dish, pour sauce over it, sprinkle with cheese.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 20 minutes. Remove from the oven and serve garnished with parsley.