Preheat your oven to 300°F (150°C).
Rub the baby back ribs thoroughly with the smoked paprika, garlic powder, sea salt, and black pepper to build a deep flavor base.
Wrap the seasoned ribs tightly in a double layer of aluminum foil, place them on a rimmed baking sheet, and slow-roast for 2 hours until the meat is tender and pulling away from the bone.
While the ribs cook, thinly slice the yellow onion into half-moons.
Heat the avocado oil in a large skillet over medium-low heat, add the onions, and cook slowly for 20-25 minutes, stirring occasionally, until they are soft and deeply caramelized.
Once the ribs are done, carefully open the foil, brush the meat generously with the sugar-free BBQ sauce, and place under the broiler for 3-5 minutes until the sauce is bubbly and slightly charred.
Steam the green beans for 4-6 minutes until they are bright green and tender-crisp.
Serve the ribs topped with a heap of caramelized onions and the steamed green beans on the side for a clean, satisfying meal.