Heat 1.5 tbsp of the olive oil in a large pan and fry the diced onion portionwise golden brown about 5 minutes while stirring. Add the pepper slices and the garlic in portions and fry them for further 5 minutes. Then add the tomato pieces and season with salt and pepper. Let the ingredients simmer over medium heat and stirr occasionally until creamy thick
Heat the remaining olive oil in a large, wide pan, fry the zucchini cubes successivley in it while stirring, and season with salt and pepper.
Give the zucchini cubes and the chopped herbs to the creamy boiled onion-pepper-tomato mixture and mix well. Season again with salt, pepper and a little sugar.
Fill the hot ratatouille brimful into prepared jars. Close the jars with twist-off caps, turn them around and let them stand for about 5 minutes. Store the ratatouille at a cool and dark place.