Spaghetti Bolognese

In a large wide saucepan or skillet over medium heat, add 1 tablespoon olive oil. Add pancetta and fry until crisp, stirring occasionally, 5 to 8 minutes.
Add onions, carrot, celery, and garlic, along with the remaining 1 tablespoon olive oil, and fry until soft, 8 to 10 minutes.
Increase heat to high, add ground beef and cook until browned, about 15 minutes. Pour in the red wine and continue to cook on high until liquid is reduced by half, about 8 minutes.
To the saucepan mixture, add the stock, milk, tomatoes, pepper, and bay leaves. Bring mixture to a boil, then reduce heat to low. Cover and simmer gently until the tomatoes have dissolved and the sauce is rich reddish-brown in color, about 1 1/2 hours, stirring every 20 minutes. Remove from heat and stir in the salt. Let rest, uncovered, for 15 minutes. The sauce can be made up to one day ahead and reheated.
☞ TESTER TIP: If your sauce looks very thin after an hour of simmering, remove the lid and let it continue to simmer until it thickens to your desired consistency.
Meanwhile, in a large pot of boiling salted water, cook the spaghetti. Follow package directions for al dente pasta, then drain in a colander.
Add spaghetti to the Bolognese, toss to combine, then divvy between four bowls. Top with grated Parmesan and serve immediately.