Wash, clean and roughly dice the tomatoes. Peel garlic and onions and cut into cubes. Wash the thyme and rosemary, shake dry, remove leaves from the stems and needles from the twigs and chop
Put the prepared ingredients into a roaster, season with salt and pepper. Braise in a preheated oven (electric cooker: 175 °C/ circulating air: 150 °C/ gas: see manufacturer) for approx. 5 hours. Stir in between. Briefly puree the finished sauce with a hand blender. Pour into clean, tightly sealed glasses and place on the lid upside down for approx. 5 minutes