Heat canola oil in a Dutch oven or large, deep skillet over medium heat. Put in the roast and get it nice and brown on all sides.
Pour off excess liquid, then add broth, vinegar, garlic, basil, and thyme. Bring to a boil, then simmer for 2 hours, flipping the roast every 40 minutes or so.
After 2 hours, add the cabbage, potatoes, onions, carrots, and red bell pepper. Season with the salt and pepper, then cook on low to simmer for 40 more minutes.
Remove meat and vegetables from Dutch oven and keep warm. In a small bowl, whisk together flour and water. Then stir into the Dutch oven. With the heat still on low, bring the sauce to a boil and simmer until thickened. Add more of the mixture if you want thicker sauce.
Serve roast sliced with gravy spooned over each serving of meat and vegetables.