After two minutes, make a low heat, add tomato paste, a glass of water and a spoonful of mustard seeds, mix, salt to taste, and leave to languish under the lid. In the meantime, do not forget about the vegetables, turning and frying on both sides until beautiful strips from the grill appear. We remove the potatoes and carrots to the sauce. Next, we grill the eggplant-remove it to the sauce, then the bell pepper, and the last onion-onion is pressed with a spatula to the grill pan. Mix so that the sauce covers all the vegetables, and simmer on low heat under the lid for 15 minutes. Done!