Cut the tomatoes and onion into large pieces or halves.
Take a baking dish and place the basil in the center (if using). Cover the basil with a layer of onion and tomato.
Add the garlic and drizzle with olive oil generously.
Bake until the tomatoes and onions show a bit of char on the skin and there are a lot of juices in the baking dish.
Peel the garlic and blend until smooth or to your desired consistency.
Notes
If adding peeled garlic, hide it under the tomatoes. If adding unpeeled, let it roast with the rest of the ingredients.
Storing Homemade Tomato Sauce
Cooling: It's important to let homemade tomato sauce cool to room temperature before storing it to prevent early spoilage due to condensation inside the container.
Choosing the Right Container:
Glass Jars: These are ideal for storing tomato sauce because they don't absorb flavors or odors. Ensure they're cleaned and sterilized.
Plastic Containers: If using plastic, ensure it's food-safe and BPA-free. Tomato sauce is acidic, and you want to avoid chemicals leaching into your sauce.
Vacuum-Sealed Bags: These are great for freezing and can save a lot of space.
Refrigeration:
If you plan to consume the tomato sauce within 5-7 days, refrigerating it is the way to go.
Pour the cooled sauce into your chosen container, leaving about an inch of space at the top for expansion.
Seal the container tightly to prevent air (and potential contaminants) from getting in.
Always use a clean spoon when serving to prevent introducing any contaminants.
Freezing:
For more extended storage, freezing homemade tomato sauce is an excellent option.
Divide the sauce into portion-sized containers or vacuum-sealed bags. This way, you can thaw just the amount you need.
Label each container or bag with the date. Homemade tomato sauce can be stored in the freezer for 4-6 months.
When ready to use the sauce, transfer it to the refrigerator for thawing, ideally a day before you need it. You can use the defrost setting on your microwave for a quicker method.