Prep the Oven and Pan: Preheat your oven to 275°F / 135°C.
Line a large, rimmed baking sheet with aluminum foil for easy cleanup later.
Prepare the Ribs: Pat the ribs completely dry with paper towels. On the bone side of each rack, slide a butter knife under the thin, silvery membrane and lift. Grab the membrane with a paper towel for a better grip and pull it off completely. This is the key to truly tender ribs, so don't skip it!
Season Generously: Brush the avocado oil over both sides of the ribs.
Sprinkle the Tennessee Dry Rub all over, making sure to cover every surface. Use your hands to gently massage the rub into the meat.
Place the ribs on your prepared baking sheet, bone side down.
Marinate (Optional but Recommended): For the most flavor, cover the ribs and refrigerate for at least 1 hour or up to 6 hours. This allows the rub to penetrate the meat. If you're short on time, you can proceed directly to baking.
Bake Low and Slow: Bake for 3 hours and 30 minutes. You'll know they're done when the meat is incredibly tender and has pulled back from the bones.
Rest and Serve: Let the ribs rest for 10 minutes before slicing between the bones.
Serve warm. Leftovers can be stored in an airtight container in the refrigerator for up to 5 days.