Step 1: Trim any excess fat from the country-style pork ribs and pat them dry with paper towels. For maximum tenderness, optionally remove the thin membrane (silverskin) from the bone side of the ribs.
Step 2: Place the prepped ribs into a large slow cooker. Pour 1 can of Dr Pepper over the ribs. Add the liquid smoke, garlic powder, and ground black pepper. Cover the slow cooker and cook on low for 6-8 hours or on high for 3-4 hours, until the ribs are incredibly tender and nearly falling off the bone.
Step 3: While the ribs are slow cooking, prepare the glaze. In a medium saucepan, combine the 1 ½ cups of smoky and tangy BBQ sauce with the remaining 1 can of Dr Pepper. Bring the mixture to a gentle simmer over medium heat, stirring occasionally. Reduce the heat to low and let it thicken for about 10-15 minutes, until it achieves a luscious, sticky consistency.
Step 4: Preheat your oven to 400°F (200°C). Line a large baking sheet with foil for easy cleanup, then place a wire rack on top. Carefully transfer the tender ribs from the slow cooker onto the prepared wire rack. Brush the ribs generously on all sides with the thickened Dr Pepper BBQ glaze. Bake for 15 minutes, then flip the ribs, brush with more glaze, and bake for another 15 minutes, or until the glaze is beautifully caramelized and sticky.