Sauté the veggies: Heat olive oil in a large skillet over medium heat. Add chopped carrots, celery, and onion. Cook until the onion is translucent, about 5 minutes.

Brown the meat (the secret step!): Add in the sausage and ground beef. Turn heat up to medium-high and cook for 30–45 minutes, stirring occasionally.

Note: Don’t rush this step. You want the meat deeply browned and almost crispy. Rendering the fat into the sauce is what makes this the best spaghetti sauce recipe. No draining necessary!

Deglaze the pan: Pour in 1 cup of beef broth while the meat is still in the skillet. Scrape up all those browned bits from the bottom of the pan — that’s pure flavor! Cook until the liquid has evaporated again. Keep adding water if needed and let it evaporate as well.

Add garlic: Stir in the fresh minced garlic and cook for 30–60 seconds until fragrant.

Build the sauce: Pour in the spaghetti sauce and stir until combined.

Add the milk and mix well.

Simmer low and slow: Reduce heat to low and let the sauce simmer gently for 1 hour. Taste along the way and adjust seasoning to your preference.