Arrange the eggplant slices in a colander.
Sprinkle all sides with salt.
Let stand for 30 minutes as the salt draws out any bitter liquid.
Rinse the eggplant well.
Heat olive oil in a frying pan.
Add the eggplant slices in batches until browned on both sides when the oil is hot.
Remove and set aside.
Continue browning the eggplant until all slices are cooked.
Lay two slices of bread side by side.
Spread some ricotta cheese and Fontina cheese on one slice.
Top with tomatoes and eggplant.
Sprinkle some salt and pepper on the tomatoes and eggplant.
Top with a fresh basil leaf and fontina cheese.
Fry the sandwich in butter until the cheese melts and the bread toasty.