I fried the eggplants on the grill (three at a time, because that's how they fit).
I mixed the yolk with the teaspoon of mustard and putting a little oil I made mayonnaise. I put it in the fridge.
I finely chopped the onion, put it in a pan and hardened it.
When the eggplants were fried, I left them to cool, then I cleaned them and left them on a slightly high shredder to one side, to drain the juice. Then I chopped it finely.
I mixed the eggplant with onions, added salt to taste and added mayonnaise.
I really like greased on a slice of bread, and on top with tomato slices :)