Edith's Low-Salt Spaghetti Sauce for One

For the last few months I've been supposed to limit my salt, so I developed this recipe for spaghetti when other people are eating the higher-sodium commercial spaghetti sauces. The vinegar adds tang, which helps me not to miss the salt. I use the Pomi brand of no-salt-added tomatoes, which come in cardboard cartons, but there are other similarly low-sodium brands that come in cans. It's important to limit the parmesan measurement to 1 Tbs to keep the sodium count down. Measures are approximate, since I usually make it without measuring cups other than for the cheese. Sometimes I include 1/4 c green bell pepper, as well. Recipe can be multiplied; just have a salt shaker on the table so folks who want salt can add it. Be sure to use some of the liquid from the tomatoes.