Start cooking meat: In a large Dutch oven or stockpot, start cooking the ground beef over medium-high heat. Break up large chunks and only stir occasionally to prevent burning.
Chop vegetables: While the meat is cooking, chop the onion, carrots, and celery. It is highly recommended that you pulse each one in the food processor to get a small diced cut.
Simmer: Add diced vegetables, tomato sauce, and about 1/2 cup of olive oil to the meat mixture. Stir well to combine and bring to a simmer. Do not cover.
Reduce heat: Once the ragu starts to simmer, gradually reduce heat and occasionally stir. The goal is to maintain a very gentle simmer and as the liquid evaporates, the heat will need to continually be reduced.
Add more olive oil. Every 30 minutes or so, add small amounts of olive oil. Once all of the recommended amount of olive oil has been added, you can decide if you want to add more. I usually add about 1/4 cup more because I like the excess oil to coat my pasta.
Add salt. After the ragu mixture has cooked for at least two hours, add salt. Stir and taste. Add more, if desired.
Serve. The longer the sauce cooks, the better it will taste. You will know it's done when the olive oil starts to pool on the top of the sauce and only low heat is required to maintain a very gentle simmer. A minimum of 3 hours is recommended. Enjoy over freshly cooked pasta.