In a bowl, combine brown sugar, paprika, black pepper, salt, chili powder, garlic powder, onion powder, and cayenne pepper to create the dry rub.
Pat the ribs dry with a paper towel and then apply the dry rub all over the ribs, ensuring every bit is covered.
Wrap each rack of ribs in two layers of aluminum foil. Make sure they are well-sealed.
Preheat your oven to 200 degrees Fahrenheit.
Place the foil-wrapped ribs on a baking sheet, bone-side down, and put them in the preheated oven.
Slow-cook the ribs in the oven for approximately 6 hours, or until the meat is tender and easily pulls away from the bone.
Remove the ribs from the oven, carefully open the foil, and brush your favorite barbecue sauce over the ribs.
Increase the oven temperature to 350 degrees Fahrenheit, return the ribs (uncovered) to the oven, and cook for an additional 10-15 minutes, or until the sauce is bubbly and starting to caramelize.
Let the ribs rest for a few minutes before cutting into individual portions.