Working in batches, quarter or coarsely chop the tomatoes and add them to the bowl of a food processor. Pulse a few times to your desired level of chunkiness.
Transfer the tomato puree to a large stockpot, then repeat Step 1 until all tomatoes are processed.
Place the stockpot over medium-high heat and bring the puree to a boil. Reduce the heat and simmer uncovered, stirring occasionally, for 30 to 90 minutes until the tomato sauce is thickened to your liking.
When the sauce is finished, let cool to room temperature, then transfer to jars and refrigerate for up to 1 week.
Alternatively, you can transfer the cooled sauce to freeze-proof containers or zip-top bags and freeze for up to 3 months.