Preheat water bath using an immersion circulator to 165 degrees F.
Season the beef well with salt and pepper. Sprinkle the flour over the beef and toss to coat.
In a large, heavy skillet, melt 2 tablespoons of butter over medium high heat. Once hot, sear the beef in batches to brown on all sides. Remove to a vacuum seal bag.
Reduce the heat to medium low. Add the remaining butter and onion. Saute until the onion begins to turn translucent, about 2-3 minutes. Add the red wine and let simmer for 1 minute. Stir in the tomato paste and let simmer until it thickens slightly. Add the mixture to the vacuum seal bag.
Add the carrots and thyme to the bag. Squish the contents to evenly distribute, then lay flat and press into an even layer. Vacuum seal.
Add the vacuum-sealed bag to the preheated water bath and cook for 24 hours. Cover with plastic wrap to help prevent evaporation.
To make the gremolata, mince together the garlic cloves and parsley. Add to a glass storage bowl. Zest the orange into the bowl. Put on the lid and shake the contents to distribute. Refrigerate until ready to serve.
After 24 hours, remove the bag from the water bath. Spoon the stewed beef over the polenta, mashed potatoes, or mashed sweet potatoes. Top with the gremolata and serve.