Preheat the grill to high. Place the chopped onions in a sheet of aluminum oil. Season with salt and pepper and drizzle with olive oil. Wrap the aluminum foil into a pouch. Then lay the eggplant out and season both sides with salt and pepper.
Lower the heat on the grill to medium and place all the eggplant on the grill. Place the onions on the grill. Grill the eggplant on each side for about 4 minutes.
Allow the eggplant and the onions to cool for 10 minutes. Chop the eggplant into half-inch pieces. Place onions and eggplant into a large bowl. Combine with EVOO, lemon juice, Italian seasoning, salt, pepper, crushed red pepper, and crushed garlic cloves. Transfer to mason jars and store in the refrigerator over night.
Enjoy on toast, sandwiches, or however you can imagine.
Notes
If you are pan-frying the eggplant instead of grilling, lay the eggplant out flat and season with salt. Let it sit for 20 minutes then pat them dry with a paper towel.
If you don't have mason jars, just tightly wrap the bowl with saran wrap.
The eggplant should be grilled long enough to have grill marks.