Preheat the oven to 400F° (200C°).
Brush the flesh of the eggplants in olive oil and place them on a baking tray. Sprinkle over them a little bit of salt and roast until the eggplants are very tender, about for 20 minutes.
Meanwhile, warm about 3-4 tablespoons of oil in a skillet over medium heat. Add the onion and garlic and stir often. Lower the heat if necessary, don’t let them brown too fast. Cook for 8 minutes then add the dried mint. Continue to cook and stir until the onion is translucent, about 5 minutes. Set a side.
Let the eggplant cool down then using a spoon, spoon their flesh and put into the skillet (if you used regular eggplants*, then put their meat into a colander, to drain the liquids). Mash them with the spoon a bit and mix with the onion and garlic. Taste and correct seasoning.
Serve in a deep plate the chopped walnuts sprinkled over and a spoonful of yogurt.
Eat with good bread or as a side.