Preheat oven to 400°F (200°C). Line a baking tray with baking paper.
Dice the eggplant and put it on the baking tray. Drizzle the oil and sprinkle salt and pepper over and rub with your hands.
Put the baking tray in the oven and roast for 15 -20 minutes – occasionally flip gently with a spatula – until the eggplant pieces are golden brown and tender.
Meanwhile, chop the onion finely and prepare the tahini.
Put the eggplant in a plate, sprinkle the onion and drizzle tahini and serve.
If you plan to serve later, store the eggplant and tahini in separate containers, and chop the onion only before you serve).
1 heaping tablespoon tahini
Juice of ½ lemon
2–3 tablespoons cold water
Put the tahini in a small bowl. Squeeze the lemon into the bowl and add 1 tablespoon water. Stir gently until the butter turns into to a thick paste. Add another tablespoon of water and stir. Keep adding water until the tahini is smooth and velvety. If it's too watery, add a little bit of tahini. If it's thick, add a little bit water.
Eat as a side or over toasted bread. Add chopped parsley, it goes well together.