Wash and coarsely dice the tomatoes. Peel onions and garlic and cut into cubes. Wash the herbs, shake dry and remove the leaves or needles. Chop rosemary. Put everything in a roasting pan and season with salt and pepper.
Braise open in a hot oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 5 hours. Stir from time to time. After approx. 4 hours, blend lightly with a hand blender and braise.
Pour the hot sauce into clean twist-off glasses and place them upside down on the lid for about 5 minutes. Let it cool down.