Step 1: Preheat your oven to 275°F (135°C).
Step 2: Prepare the ribs. Remove the membrane from the back of each rack of ribs. Trim any excess fat.
Step 3: In a small bowl, combine brown sugar, smoked paprika, garlic powder, onion powder, salt, and black pepper. Mix thoroughly to create the dry rub.
Step 4: Generously rub the spice mixture all over both sides of the ribs. For best results, let the ribs sit with the rub for at least 30 minutes at room temperature, or refrigerate for 2-4 hours (or overnight).
Step 5: Place each rack of ribs, meat side up, onto a large piece of heavy-duty aluminum foil. Pour about 1/4 cup of apple juice or water over each rack.
Step 6: Tightly seal the foil around the ribs, forming a secure packet. Place the foil-wrapped ribs on a baking sheet.
Step 7: Bake in the preheated oven for 2.5 to 3 hours, or until the ribs are very tender. You should be able to easily insert a toothpick into the meat with little resistance.
Step 8: Carefully remove the ribs from the oven. Increase the oven temperature to 375°F (190°C). Open the foil packets, drain any accumulated liquid, and transfer the ribs to a new, clean baking sheet lined with parchment paper or foil.
Step 9: Generously brush both sides of the ribs with your chosen BBQ sauce.
Step 10: Bake for an additional 15-20 minutes, or until the sauce is caramelized and slightly sticky. Watch carefully to prevent burning.
Step 11: Remove from the oven and let the ribs rest for 5-10 minutes before slicing. Slice between the bones and serve immediately.