Start by frying the onions if you are using fresh onions. Cook until transparent.

Place the tomato sauce in the saucepan with the onions along with the salt and pepper.

Add in the oregano and chili powder. You may also need to add in some water if you are using tomato sauce. The sauce should be fairly thin, not thick like spaghetti sauce.

Cook the spaghetti noodles until al dente.

Simmer the tomato gravy until heated through and bubbly. If you use tomato juice, you might want to use a little flour to thicken it slightly. For stewed tomatoes, my granny would just mash up but not blend. I guess the chunks were half the fun! You can do what you'd like.

Drain your pasta and serve the gravy over the noodles. That's it!