Preheat your oven to 325°F and prepare a baking dish with cooking spray or by lining with aluminum foil.
In a small bowl, mix together the garlic powder, onion powder, smoked paprika, salt, and black pepper to make a dry rub.
Rub the dry rub all over the country-style ribs, making sure to coat them evenly.
Place the ribs in the prepared baking dish and cover with foil.
Bake the ribs in the preheated oven for 2-3 hours, or until the meat is tender and falls off the bone.
Remove the foil and brush the ribs with BBQ sauce making sure to coat them evenly.
Return the ribs to the oven, uncovered and bake for an additional 15 minutes, or until the BBQ sauce is caramelized and sticky.
Remove the ribs from the oven and let them rest for a few minutes before serving.
Serve hot with your favorite sides.
Serving Size Notes: A general rule of thumb is to estimate about 1/2 to 3/4 pound of ribs per person, depending on how meaty the ribs are and what else is being served with them. 5 pounds of ribs will serve around 6-10 people.