Have all ingredients measured and ready to go.
Boil water, salt generously, and cook pasta 2 minutes LESS than packet instructions.
While pasta cooks, heat olive oil in a skillet over high heat. Add bacon and cook for 1 minute until crisping. Add garlic and onion, cook 3 minutes until onion is translucent and bacon is golden. Drain excess fat if desired.
Reserve a mug of pasta water. Add about 1/2 cup to the skillet. Simmer and stir, scraping up browned bits from the bottom.
Add crushed tomatoes to the skillet. Bring to a simmer for 2 minutes, then reduce heat to medium-high.
Drain pasta (or use tongs to transfer directly into the skillet with the sauce).
Toss pasta gently with the sauce for 2 minutes until pasta is well-coated and sauce has thickened. Add reserved pasta water, a splash at a time, if needed.
Season with salt and pepper to taste, remembering bacon is salty.