In your dutch oven or sauce pan, over medium heat, add the ground beef and onions to start cooking. Cook until the onions are turning translucent, stirring regularly.
Add the garlic, stir, and cook, stirring regularly, until the meat is done.
Drain excess grease from the meat.
Add in the tomato sauce and diced tomatoes, stirring well.
Mix in the mushrooms, oregano, basil, and salt. Stir together and reduce the heat to medium-low.
Simmer for at least 15 minutes, stirring occasionally to keep the bottom from burning.
Adjust for your preferred thickness (see blog post) and simmer until ready to serve.