In a mixing bowl, put round eggplant slices in salt water for at least 30 minutes. After 30 minutes, drain water and use a paper towel to dry the eggplants.
Using a grill pan, season grill with oil, Italian seasoning and salt. Let is heat up.
Grill eggplants until tender and cooked on both sides.
Butter each side of sour dough bread. Toast on grill pan until light brown.
Spread hot pepper spread on toasted bread.
On one slice of toasted bread, add sliced tomatoes and grilled eggplant slices.
On other slice of toasted bread, add mozzarella cheese.
Put slices together and grill for a few minutes.
When ready to serve, slice sandwich in half and drizzle balsamic glaze.