mix 1-2 tablespoons of balsamic vinegar and 1 – 2 tablespoons of olive oil in a bowl. whisk it together; dip the chicken breasts in, coating both sides. set aside on a grill pan. salt and pepper both sides of the chicken. sprinkle rosemary on both sides. grill in oven (or on indoor/outdoor grill) until chicken is done. keep warm in the oven.
brush olive oil on both sides of the eggplant slices. salt and pepper both sides. grill 2-3 minutes per side until tender (but not mushy).
meanwhile, add olive oil (two turns of the pan) to a pan, heat up and saute chopped onion, garlic, and crushed red pepper until onions are tender. add can of tomatoes and heat through. season with salt and pepper.
on baking sheet, arrange stacks by placing a chicken breast, top with an eggplant slice, a large spoonful of the sauce, and a slice of mozzarella. repeat the stacks. broil in the oven until mozzarella is melted and browned on top.
serve the stacks with a little sauce on the side. you can serve this dish with pasta tossed with some grated parmesan (i prefer angel hair), a salad, and/or garlic knots.
it’s really delicious and the sauce is just spicy enough for a good little kick, but not so hot you can’t eat it.