Before you turn the grill on, spray in order to help with the vegetables to not stick. Then turn on medium heat. Add on the slices of sour dough & grill for about 10 minutes.
Then place 3 slices of grilled sourdough bread on a baking sheet, and spread garlic aioli on top of each slice. Then layer grilled eggplant slices on each piece of bread, then the grilled tomatoes.