Over medium heat, sauté pancetta in olive oil until all fat is rendered and evenly browned.
Once rendered, add the onion, celery, and carrots. Cook until all the vegetables are soft, and the onions are translucent about 8-10 minutes.
Remove the cooked vegetables and pancetta from the pot and set aside.
Over medium-high heat, add the trimmed and finely chopped skirt steak to the empty pot.
Season the beef with kosher salt and black pepper.
Reduce the heat to medium and cook the beef pieces until well browned about 10 minutes. DO NOT OVER-COOK; the individual pieces of skirt steak should be evenly browned and not crusty
Return the cooked vegetables and pancetta to the pot, stirring to combine, and cook until most of the liquid has evaporated.
When all the liquid has evaporated from the pot, add the white wine to the deglazed pan.
Let simmer on medium heat until most of the wine has evaporated.
Move some of the mixture to create an open space and add the tomato paste. Stir to combine and let simmer a couple of minutes.
Add enough stock to barely cover the meat.
Reduce the heat to low. Cover the mixture with a cartouche, then cover the pot with the lid and simmer for 45 minutes.
Remove the cartouche and set aside.
Still over low heat, add a little milk, about ¼ cup at a time, to the mixture to make it saucy. Stir to combine.
The cooktop should remain on low. From this step on, the ragu should be at a slow simmer, which gives it maximum flavor.
Cover the mixture with the cartouche, then cover the pot with the lid and simmer for another 30 minutes.
After the 30 minutes, add a little more milk, about ¼ cup, to make it saucy. Stir to combine.
Repeat this step two more times. This step's total cooking time is another hour.
When the Bolognese is finished cooking, after almost three hours, add the warmed cream a little at a time, gently stirring as you add the cream.
Serve with your favorite pasta and top with grated cheese and hot peppers if desired.