- Heat 30 mL (2 tbsp.) oil in a saucepan over medium heat and fry the onion for 5 minutes. Add garlic and cook, stirring, for 2 or 3 minutes.
- Add the tomatoes, salt, pepper, and remaining oil. Bring to a boil. Reduce heat and simmer for 45 to 60 minutes, stirring occasionally, until sauce is thick.
- If you'd like a smoother sauce, purée it with a hand blender.
- Add basil and simmer another 5 minutes.
- Place sauce in sterilised Mason jars, leaving 1 cm (½ in.) of space at the top of each jar.
Seal and sterilize.
This recipe's acidity level means it can be canned using the boiling water technique.
• Sterilize jars by immersing in boiling water for about 5 minutes.
The lids must be new to ensure a proper seal. Soak lids in hot water before using.
• Fill jars, leaving a headspace of about 1 cm (½ in.).
• Place lids and screw bands on jars but do not over-tighten.
• Immerse jars in boiling water and boil for at least 15 minutes.
• Remove jars from water and let rest for 24 hours.
The lids will be depressed and make a sudden popping noise when the seal is tight.
• The jars can be stored for one year in a dark, dry, cool place.