Preheat the oven to 325 degrees F. Make 10 slits throughout the roast. Stuff a clove of garlic in each slit. Rub the entire roast with the olive oil. Season with salt and pepper. Heat a large skillet, over medium heat. When the pan is hot, sear the roast on all sides, about 3 to 4 minutes. Remove from the pan and place the roast in a Dutch oven with a cover. Add the stock and cover. Place in the oven and cook for 4 hours. In a mixing bowl, toss the vegetables with olive oil. Season with salt and pepper. Place the vegetables around the roast and cover. Cook for additional hour. Remove the roast from the oven and arrange on a serving platter, reserving the liquid. Whisk the flour and water together. Pour the reserved liquid and grime into a saucepan and bring to a simmer. Whisk the flour mixture into the reserved liquid. Bring the liquid back to a simmer and cook for 4 to 6 minutes. Season with salt and pepper. Serve with the pot roast.