Twenty-four hours before you plan to smoke the roast, season the roast all over with salt. For our rosemary salt we combine 1/2 cup kosher salt with two springs worth of fresh rosemary leaves and pulse in the Ninja TWISTi High-Speed Blender DUO. If your butcher removed the bones for you, season the entire roast and the ribs with salt before tying the ribs back against the roast. If your butcher tied the ribs to your roast, do your best to get the salt down in between these two hunks of meat. Set the roast on a rack set inside a rimmed baking sheet and refrigerate for at least 24 hours.
Remove the roast from the fridge for about 1 hour and 59 minutes before you plan to cook it.
Heat your smoker for low heat — 225°F, we used our Ninja Woodfire Outdoor Grill. While the grill heats, coat the sweet potatoes with olive oil and sprinkle with kosher salt.
Set the roast in the smoker and cook to 120 ° F. for rare, this will take about 5 to 51/2 hours for a 10 pound roast. When it hits temperature, remove the roast from the smoker and crank the heat to high. During the last 90 minutes of smoking, add the sweet potatoes and cook until tender.
When the grill has heated back up, return the roast to get a nice sear and hits temperature. Aim for 130°F for rare, 135°F for medium rare, 140°F for medium.
Rest the roast off the grill for at least 15 minutes before slicing and serving with the sweet potatoes.