**Before starting, please be aware that sterilizing your canning jars and lids is very important! Improperly sterilizing the jars and lids can be very dangerous to your health. There are various methods to sterilize your jars and lids, but make sure that they are fully dry and still very warm once you are ready to add in the tomato sauce.
Start off by washing the tomatoes thoroughly. Cut off the top part of the tomatoes to remove the stem and cut off any bruised spots. Slice the tomatoes down the middle. Cut out any yellow pieces found inside. Lightly squeeze the seeds and water out into a bowl and then place the tomatoes into a large pot. Discard the seeds and water.
Place the pot of tomatoes over a high flame and cook for 45 minutes. Make sure to stir every couple of minutes so that the tomatoes are cooking evenly. Remove the pot from the flame and scoop out some of the tomatoes and place into a colander over a separate pot to let the water strain.
Next, place those tomatoes into an electric tomato press and allow for the skin to be removed while the pressed tomatoes are poured into a separate bowl. Pour the pressed tomatoes into a separate clean pot. Repeat this step until all of the tomatoes have gone through the tomato press. Discard the tomato skins.
Place the pot of the pressed tomatoes back over a high flame and cook for three to four hours stirring occasionally, so that the sauce does not burn. The longer it cooks, the thicker the sauce gets. About twenty minutes before you are done cooking the tomato sauce, season with some sea salt.
Once the sauce is done cooking, ladle the tomato sauce into the mason jars. I use a funnel to quickly pour the tomato sauce into the jars so that I don't spill any. Leave some space at the top of the jar. Add two basil leaves into each jar and push them down into the sauce with a spoon. Seal each jar tightly so that no air can get in. Place the jars in a box and cover with a thick blanket to insulate the jars and allow to continue to cook for another 48 hours. After 48 hours, place in a cool place, like your basement. This is a very basic sauce that allows you to make various different recipes. Once you are ready to use the jars, you can season them with whatever you like, depending on the recipe. You can use this for pizza sauce, steak pizzaiola sauce, chicken parmigiana, or even Sunday sauce with meatballs and braciole.