On a large plate, stir together the flour, 1 teaspoon salt, and 1/2 teaspoon pepper.
Turn the roast in the seasoned flour, shaking off any excess.
In a large skillet, heat the butter and oil over medium-high heat.
Add the roast and cook, turning occasionally, until browned on all sides, about 8 - 10 minutes.
Remove from the pan and set aside.
Add the pancetta to the pan and cook over medium-high heat until the fat is rendered and has just become crisp. Use a slotted spoon to transfer to a paper towel-line plate. Set aside.
Pour off all but 1 tablespoon of the fat in the pan.
Add the onion, celery and carrots and sauté until soft, about 6 minutes.
Add the garlic and cook for another 1 minute.
Add the mushrooms and cook until they begin to release their liquid, about 8 minutes.
Reduce the heat to medium and continue cooking until most of the liquid has evaporated, about another 10 minutes.
Pour in the wind and scrap up the brown bits stuck to the pan with a wooden spoon.
Stir in the stock, tomatoes, rosemary and basil and bring to a boil for 3 minutes.
Stir in the pancetta and season with a healthy pinch of salt and pepper.
Pre-heat the oven to 325°F.
Transfer the roast to a large Dutch oven (or other oven-safe vessel).
Pour in the wine and mushroom mixture.
Cover and cook, stirring occasionally, until the roast is tender, about 4 hours. (You can also do this in your slow cooker, set on the low setting, for 10 hours).
Transfer the roast to a cutting board and cover with aluminum foil to keep warm.
If the sauce is too thin, pour the cooking liquid into a saucepan, bring to a boil over high heat, and cook until it thickens slightly.
Taste and add salt, if desired.
Cut the roast in thick slices with a sharp knife.
Arrange the slices on a large platter, or serving plates, and top with with sauce.