Cut the eggplant into medium-sized cubes and place in a colander. Sprinkle generously with salt and set aside for 30 minutes to 1 hour, if possible. If you can, weigh it down with something heavy (we use a plate with our mortar and pestle on top).

Meanwhile, wash and cut the celery into small pieces. Bring a small pot of water to a boil and salt it well. Add the celery and boil for 10 minutes. Remove it with a slotted spoon to a bowl and reserve the cooking water for later.

Rinse the eggplant under cold running water for a few seconds, then dry it well with a clean kitchen towel. Heat the sunflower oil in a heavy-based pan at least 1 inch deep. Once hot, fry the eggplant in batches until lightly golden. Remove and drain on kitchen paper. Sprinkle with salt.

Heat 1-2 tablespoons of olive oil in a large pan and add the sliced onion. Sauté for 5 minutes until softened, then add the celery, olives and capers. Next, add the tomato paste with 1 cup (250ml) of reserved celery water, stir to combine.

Turn off the heat and uncover. Taste for seasoning and add more salt if needed. Leave to cool to room temperature before serving (it tastes even better the next day).