Ultimate healthy homemade tomato sauce (+preserves)

Cut the tomato, the onion and the bell pepper and sauté them with the spoonful of oil in a casserole for about 10-15 minutes. When everything is soft and the onion has some color, it is beaten in the casserole.

Add the herbs and spices to taste, whisk again, taste and adjust if necessary.

While we were cooking it, we had to boil glass jars and their metal lids (uncovered) to sterilize them. It is important that neither the jar nor the lid have marks or bumps. We boiled them for about 20 minutes, well covered with water, and carefully took them out to dry on a cloth.

When the sauce is ready, put it immediately and still hot in the jars (almost full, but leaving a few millimeters or half a centimeter at least). Close them very tightly and put them in the pot with water that covers them. We boil them for 30 minutes.

Carefully remove them from the water, tighten the lid again and let them cool slowly face down on a cloth. Place another cloth on top of them so that they slowly lose heat. When they are cool, tighten the lid again just in case and they can be stored for months in a cool, dry place away from sunlight. When you open one, you should hear a "plop" and, once opened, it should not be kept for more than a few days, always kept in the refrigerator.