Cut potatoes into 2-3 inch round slices. Deep-fry them. Cook ground beef, Tat Practical Diced Tomatoes with Onions and Peppers and chopped onions in a saucepan. For the béchamel sauce, in another saucepan, add brown flour with butter, and then add milk. Put the fried potatoes on a paper towel so it can soak the excess oil. Preheat the oven at 180 degrees. Place the potatoes in a pot; add the ground beef mixture and béchamel sauce. Add parmesan cheese and cook for about 25 minutes until golden brown. Serve hot.