First you need to mix the hamburger with the diced onions in a mixing bowl . Now roll the hamburger into golf ball sized meatballs with your hands. By using your hands, you have much more control over the hamburger and you can ensure that it is getting mixed thouroughly. You can also assure that you will be able to measure out the meatballs more evenly this way.
Now bring a kettle of water to a boil and add a tablespoon of butter to prevent the spaghetti noodles from sticking. Add the noodles to the boiling water. Allow 10 minutes of boiling time for the noodles. A great trick to test if the noodles are done or not is to take one noodle out of the boiling water and literally throw it at the wall. If it sticks to the wall, it is ready!
Start frying the meatballs in a frying pan. Since hamburger is already fatty, you will not need to add oil. As the meatballs begin to fry, their own natural oil comes out and begins the browning process. You want to get your meatballs good and brown. Personally, I like them with a little burnt flavor.
Once the meatballs are good and browned, almost burnt, add your favorite spaghetti sauce into the frying pan.Stir in the sauce right in with the cooked meatballs. Lower the heat to simmer and strain your spaghetti noodles into the sink using a colander.
Once the spaghetti noodles are soft, strain the noodles with a colander. This allows the excess water and oils to be strained out from the noodles. After you have them strained, put them back in the kettle you were boiling them in.