1. Slice and blend the tomatoes into a puree, then transfer to a saucepan and bring to a boil.
2. Skim off any foam that forms on the surface while boiling, then continue boiling for a couple more minutes before turning off the heat.
3. Pierce the tomatoes with a fork and place them in sterilized glass jars. Fill the jars with the tomato puree.
4. To seal, immerse the jars in boiling water in a pan to create a vacuum. Store in a cool, dry place.

Ensuring a tight seal and vacuum is crucial for extending the tomatoes’ shelf life. With this method, you’ll always have homemade preservatives at your fingertips, ready to elevate any dish, from a quick spaghetti to flavorful seasonings!