Tip:To adapt a slow-cooker recipe to a conventional oven, follow these guidelines: add more liquid, to accommodate for greater evaporation; bring the dish to a boil over high heat in a Dutch oven, then cover the pot and put in a 350°F oven. Plan on the dish taking roughly half the time to cook in the oven as it would in the slow cooker.
With a wooden spoon, mix together 1⁄4 cup of the orange juice, 2 Tbs. garlic, 1 Tbs. tomato paste, and the sage. Add the meat and coat it all over with the marinade. Sprinkle evenly on all sides with the salt and pepper.
Meanwhile, heat the butter in a 10-inch, heavy sauté pan over medium-high heat. When melted, add the onions, celery, carrots, parsnips, and the remaining 1 Tbs. garlic and sauté, stirring occasionally, until the onions are very soft and the vegetables are starting to take on a hint of brown, about 10 minutes.
Stir in the remaining 1⁄4 cup of tomato paste and the flour, and cook until the flour is no longer visible, no more than 1 minute. Remove the pan from the heat and add the wine. Return the pan to the heat, and raise the heat to high. Stir until the sauce thickens, about 2 minutes. Add the tomatoes, the remaining 1⁄2 cup orange juice, the stock, honey, and rosemary, and boil for 5 minutes. Use a potato masher to gently crush the tomatoes, and stir the sauce.
Pour the sauce over the meat in the slow cooker, cover, and cook on low until fork-tender, about 10 hours (ideally, turn the meat over halfway through to cook it evenly). Remove and discard the rosemary, then use a large spoon or ladle to skim the fat off the surface of the sauce. Transfer the meat to a cutting board and cut off and discard the kitchen twine. Cut into chunks (the meat will be too tender to slice) and return to the sauce. Spoon the meat and sauce over the polenta.