Step 1. Place the eggplants on a cookie sheet and roast in the oven at 400° for one hour.
Step 2. Peel the skin off and place egg plants in a glass bowl to let them drain. Drain them overnight in a plastic colander (Stainless steel will discolor the eggplant).
Step 3. Remove all the liquid and place eggplants in the food processor. Process for 30 seconds or until eggplants are chopped. Add shredded onion, salt, and mayonnaise. Mix and serve cold over bread, with crackers, or as a side dish to any meal.