Take your meat out of the fridge 2 hours prior to cooking to bring down to room temperature. Preheat oven to 240c (220c if fan-forced), and combine 10 tbsp butter, rosemary, thyme, garlic, and pepper in a bowl. Pat meat dry with a paper towel, and turn it over, so that the side with the bones is now on top. Rub meat with 1 tbsp of salt, then smear a quarter of the butter mixture onto the meat.
Place onions, shallots, and halved garlic head in the centre of a roasting pan. This will function kind of like a rack for the meat to allow for better air circulation. Turn meat over, so that the buttered bone side is now on the underside, and the fat cap, meaty side is now facing upward towards you. Repeat with the remaining salt, and remaining butter, reserving about 1 tbsp of the mixture. Place in hot oven for 20 minutes.
Remove from oven, and turn the heat down to 120c (100c if fan-forced). Whilst waiting for the oven to cool (leave the door ajar so heat can escape), add the remaining butter mixture onto the meat. Toss the potatoes in a bowl with an additional tbsp of butter, salt, and pepper. Add potatoes and pumpkin to the pan around the meat, and top with sprigs of thyme and rosemary. Once oven has cooled, cook meat for an additional 1.5 hours (rare), basting with the juice and drippings every 30 minutes, and lightly tossing the vegetables too.
When meat has reached desired internal temperature, remove from oven. Use tongs to transfer meat to a cutting board to rest with foil lightly draped over it for at least 30 minutes, and place vegetables/dried herbs into a bowl. You can keep them warm in the oven too. Move pan to the stove, and heat remaining drippings on medium-high. Add in wine to deglaze the pan, using a metal spatula to scrape the bottom. Once wine has reduced by half, add in beef stock and cook on high for 3-4 minutes, stirring frequently with a whisk and allowing it to simmer rapidly. Turn off heat, add in balsamic vinegar, and season with salt and pepper. Pour through a sieve to get rid of any bits of dried herbs.
To serve the meat, simply slice it along the bones (which will yield about 4 pieces), then remove the bone from each piece and slice it in half again for a total of about 8 pieces. Serve with balsamic jus poured all over the meat and vegetables and enjoy.
**NOTE 1: Remove the meat from the oven when it is about 2-3 degrees away from reaching the desired internal temperature. As it rests, it will continue to heat up slightly.
**NOTE 2: How do I scuff my potatoes? After you peel and parboil them, drain them in a colander and place the pot lid over the colander. Hang onto the sides, clamping down the lid, and toss them vigorously a few times until they are scuffed. This helps to crisp them up slightly in the roasting process and yields a nice texture.
