Preheat your oven to 300°F or prepare your smoker for indirect low heat.
In a small bowl, combine the sea salt, black pepper, garlic powder, onion powder, and smoked paprika to create the dry rub.
Season the beef brisket on all sides with the dry rub, pressing the spices firmly into the meat to ensure they adhere.
Wrap the brisket tightly in a layer of parchment paper followed by a layer of heavy-duty aluminum foil.
Place the wrapped brisket on a baking sheet and roast for 3 to 4 hours, or until the internal temperature reaches 195°F.
While the brisket cooks, whisk together the tomato paste, apple cider vinegar, honey, and yellow mustard in a small saucepan over low heat to thicken the glaze.
During the last 25 minutes of cooking, toss the halved Brussels sprouts with olive oil and roast at 400°F on a separate tray until charred and tender.
Carefully unwrap the brisket, brush the top generously with the prepared BBQ glaze, and broil for 3-5 minutes until the glaze is bubbling.
Allow the meat to rest for 15 minutes before slicing thinly against the grain and serving with the roasted sprouts.