Prepare the vegetables: Dice the eggplants, zucchinis, potatoes, and peppers into large cubes.

Sauté the onion: Heat the olive oil in a pot and soften the onion over low heat.

Add the vegetables: Add the potatoes, eggplants, zucchinis, and peppers in order, stirring gently.

Add tomatoes and spices: Add the tomatoes, salt, and sugar. Pour in the hot water and cover the pot.

Cook over low heat: Cook over low heat until the vegetables are tender (30–35 minutes). Serve after resting at room temperature.