(Optional, for long-term storage) Sterilize the jars and lids in advance. I usually place the lids in boiling water and steam-sterilize the jars for 15 minutes. Let them dry on a clean kitchen towel.
Bring a large pot of water to a boil.
Meanwhile, wash the tomatoes thoroughly.
Score a shallow "X" on the top of each tomato.
Once the water is boiling, add the tomatoes and boil for about 5 minutes.
Remove the tomatoes, rinse them under cold running water, and let them cool slightly.
Gently peel off the skins, starting from the scored area.
Dice the tomato flesh into small cubes.
(Optional, for long-term storage) When the jars and lids are dry, fill the jars with the diced tomatoes, leaving about 2 cm (1 inch) of headspace. Seal the jars and pasteurize them in boiling water for 30–40 minutes (time may vary depending on the size of the jars).
