Here are the simple steps:

To start, preheat your oven to 275 degrees. Line a baking sheet with parchment paper. Core and cut the tomatoes in half and lay them out on a baking sheet, cut side up. Now it’s time to dress them up a bit. Drizzle the tomatoes with olive oil and add some garlic cloves to the tray. Add some fresh herbs such as oregano, thyme, rosemary and basil.

The roasting time will vary on the type of tomato. Meatier tomatoes like San Marzano (Roma Types) will need less time to roast—typically about 3 hours—whereas larger heirloom types might need to roast for 3 to 5 hours. After roasting, remove the tomatoes from the oven and let everything cool to room temperature. Pour the whole roasted mix into freezer bags and place them in the freezer. 

When you are ready for fresh sauce, defrost the bag in the refrigerator, and once thawed, pour everything into a pot to season and cook. Now you can have a delicious sauce anytime, even in the dead of winter.