Sprinkle salt and pepper all over the roast.
Kosher salt and freshly ground black pepper, 1 4 lb rump roast
Add the flour to a large platter and dredge the roast through it until fully covered with flour. Shake off excess.
½ cup all-purpose flour
In a large skillet, heat the butter and oil over medium-high heat.
2 tbsp unsalted butter, 2 tbsp olive oil
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.
4 oz pancetta
Add the onion, celery, and carrots and sauté until soft, about 6 minutes.
1 cup onion, 1 cup celery, 1 cup carrots
Add the garlic and cook for another 1 minute.
3 cloves garlic
Add the mushrooms and cook until they begin to release their liquid, about 8 minutes.
½ lb fresh mushrooms
Pour in the wine and scrape up the brown bits stuck to the pan with a wooden spoon.
2 cups red wine
Stir in the stock, tomatoes, rosemary, and basil, and bring to a boil for 3 minutes.
1 cup beef stock, 1 28 oz can whole tomatoes, 2 tbsp basil, 1 tbsp rosemary
Stir in the pancetta and season with 1 tsp salt and ½ tsp pepper.
Preheat the oven to 325°F.
Transfer the roast to a large Dutch oven (or another oven-safe vessel).
Pour the sauce over the top of the roast.
Cover and cook for about 1½ hours, or until the internal temperature reaches 145°F for medium. (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 it with aluminum foil to keep it warm.
If the sauce is too thin, pour the cooking liquid into a saucepan, bring it to a boil over high heat, and cook until it thickens slightly.
Taste and add salt, if desired.
Cut the roast into thick slices with a sharp knife.
Arrange the slices on a large platter, or serving plates, and top with with sauce.