Place ground beef and chopped onion in a saute pan set over medium heat and cook until beef is browned and onion is tender. Add garlic and cook for an additional minute, until the garlic is fragrant.
Add all remaining ingredients and stir to combine. Bring to a boil, then reduce to a gentle simmer and cook uncovered for 10 minutes, or until sauce has thickened and noodles are tender.
Serve immediately.
Notes
Optional additions include shredded cheese, crushed red pepper flakes, or even a little bit of hot sauce.