1. Preheat grill to medium high
2. Place eggplant rounds in baking sheet and sprinkle with salt. Coat both sides lightly with cooking spray. Combine parmesan (or asiago) and mozarella in a small bowl. Brush both sides of focaccia (or bread) with oil
3. Place spinach in a large microwave safe bowl. Cover with plastic wrap and punch several holes in the wrap. Microwave on high until wilted, 2 to 3 minutes. Combine tomatoes and 2 Tbsp basil in a small microwave safe bowl. Cover and microwave until bubbling, about 2 minutes.
4. Place all your ingredients on the baking sheet with the eggplant and take it to the grill. Grill the eggplant slices until brown and soft on both sides, 2 to 3 minutes per side. Grill the bread until toasted about 1 minute per side. Return the eggplant and bread to the baking sheet. Reduce grill heat to medium.
5. Place 1 eggplant round on top of each slice of bread. Layer 1 Tbsp tomatoes, 1 Tbsp cheese on each slice of eggplant. Repeat with the remaining eggplant, sauce, spinach, and cheese. Sprinkle each stack with some of the remaining basil. Place the baking sheet on the grill, close the lid and grill until the eggplant stack is hot and the cheese is melted, 5 to 7 minutes.
