To prepare a simple tomato sauce, first fry a thinly sliced onion to a light brown, then add sieved tomatoes, basil and salt. While the sauce is cooking over low heat, bring a pot of salted water to a rolling boil. Cut the bread into slices (approx. 2-inch) and put them into the boiling water. Then remove them and let the water drip off. Put two spoonfuls of sauce and some grated cheese in a bowl. Put a layer of bread slices on the sauce and cover them with more sauce and cheese. Repeat the layering of bread and sauce. After a few minutes, the bread will absorb the sauce and the dish will be ready to serve.