Rub salt on all roast surfaces, set roast out to temper at room temperature while you prepare the other ingredients.
In a large bowl or bag, combine remaining ingredients except for garlic, onions, and broth, shake or stir to coat well. Set aside.
Preheat Dutch oven or large pot over medium-high heat. Add oil, brown roast well on all sides.
Scatter onions around the roast, place garlic on top (not touching the pan). Cover with a heavy lid or tightly with foil, roast in the oven for 30 minutes.
Remove from the oven, carefully cut roast into 4 pieces. Add vegetable mixture, stir together. Pour broth over meat and vegetables, recover, and place back in the oven.
Lower oven heat to 300F and roast 2-3 hours until meat is fork-tender.