Blanch your tomatoes briefly (quick cooking) in hot water for about 30-60 seconds.
Peel tomatoes, quarter them and cut them into smaller chunks.
Slice your onion, chop your garlic or take it through the garlic press.
Place onion, garlic, and tomatoes into a large cooking pot and pour olive oil over that. Heat up and keep over a medium heat setting at all times.
Season with black pepper, salt, sugar, and bay leaf. Also, add your fresh herbs.
Stir and bring to a boil.
Cook over medium heat until tomatoes are soft.
Take out and discard all hard herb pieces and the bay leaves.
Blend smooth with a hand blender.
To can the coulis
Wash your jars well. You can boil them in water too for an extra layer of protection (optional) to sterilize your jars further.
Boil rubber gaskets in water to kill all germs. (this is a must!)
Place rubber gaskets over jar lids. Work with clean hands. Pour tomato coulis into each jar up to the top.
Keep water bath canner on the stove and place jars next to each other and over each other into the canner. They should all fit in.
Cover all jars well with water and close the canner with the lids. Fix the thermometer too.
Heat up water bath canner to 210 Fahrenheit or 100 Celsius. This takes about 1 hour over a high heat setting.
When done, open lid. Keep a kitchen cloth spread out ready on a nearby kitchen surface.
Take out each jar with a jar lifter and place on the cloth to cool and drain.
When cooled, place and store your jars in a cool and dry place away from sunlight.
Video
Notes
Use your favorite tomatoes. Can be classic red varieties or yellow, orange or even black. I like to use beefsteak tomatoes (it's a variety of large tomatoes) if I can get them.
Pick some fresh mixed herbs. Combine as you like. You can use basil, marjoram, oregano, chervil, parsley, thyme, savory, and lovage. A bundle of fresh herbs is about 1.5 ounces or 45 grams heavy.