Cut the black Grenadier fillet into small pieces (3-4 cm) and dry with paper towels (they will absorb excess moisture). Then roll the fish in starch and fry in vegetable oil until light Golden brown. Put the finished pieces on paper towels.
Prepare the vegetables for the stew: coarsely chop the onion and bell pepper, peel and cut the celery into slices, remove the skin from the tomatoes and chop them into cubes.
Wash the pan after the fish and heat it up. Add the vegetable oil and fry the vegetables, placing them on the pan sequentially to ensure even roasting: onions with pepper, then celery and last of all-tomatoes and garlic.
In the pan with the vegetables, send the fried pieces of fish. Add water, pesto sauce, salt and sugar. Simmer the stew over medium heat for 5-7 minutes, stirring occasionally. Serve the dish in a deep dish, garnished with herbs.