In a large skillet over medium high heat, cook the 1/2 pound ground beef, 1/2 pound spicy Italian sausage, 1/2 teaspoon red pepper flakes, and 1/2 teaspoon kosher salt until brown and crumbly. Transfer to a plate.
In the same pan, heat 2 tablespoons extra-virgin olive oil over medium high heat. When the oil is hot, add 1 medium onion and sauté until the onions become very soft, about 8-10 minutes. Add the 4 garlic cloves, 1 stalk celery and 1 carrot and sauté for 5 minutes.
Add cooked meat back to the pan and stir well to combine.
Add the 28-ounce (one large can) crushed tomatoes, 1/4 cup flat-leaf Italian parsley and 8 fresh basil leaves, cover, and cook over medium low heat until the sauce thickens, at least 30 minutes but longer is better. Serve Bolognese with pasta and freshly grated Pecorino Romano.
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Notes
Notes: Sauce is even better the next day. If you're prepared, make it a day in advance instead!