Heat the oil in a heavy large pot over medium-low heat. Add the onions and rosemary. Sprinkle with salt and pepper and sauté until the onions are translucent, stirring frequently, about 12 minutes.
Add the tomato paste and cook and stir for 1-2 minutes. Add as many tomatoes to the pot as will fit. Add the Parmesan rinds. Simmer, adding more tomatoes as the tomatoes settle down and make space. After all the tomatoes have been added, simmer uncovered until the tomatoes are very tender and mostly disintegrate and sauce thickens to thin tomato sauce (it will be thicker when pureed), occasionally stirring and breaking up tomatoes with spoon, about 2 hours.
Place the herbs on a cutting surface. Sprinkle with salt and chop finely. Add to the sauce. Simmer a minute or two to blend flavors. Let the sauce cool slightly. Discard cheese rinds, and rosemary sprigs, and then, puree with an immersion blender. Taste and adjust the salt and pepper. Let cool completely.
Mark a 1-quart freezer bag with date and “tomato sauce.” Place the bag in a large mug, glass or widemouthed canning jar and fold the edges over the rim. Spoon in about 2 cups of sauce. Place the filled bag flat on the work surface and coax out any air. Zip closed. Repeat with remaining sauce. Place bags of sauce on a baking sheet and freeze until firm. When frozen, the bags can be stacked. Thaw in the refrigerator before reheating and spooning over freshly cooked pasta.