Preheat the oven to 375 degrees. Line a large baking sheet with foil.
Pat the ribs dry and rub them all over with 2 tablespoons of the olive oil, 1 teaspoon of the salt, the black pepper, paprika, and garlic powder.
Place the ribs on the baking sheet in a slightly curved shape so they resemble a rib cage.
In a large bowl, toss the carrots, parsnips, sweet potatoes, and red onion with the remaining 1 tablespoon olive oil and 1 teaspoon salt.
Spread the vegetables around the ribs on the same baking sheet.
Roast for 1 hour and 15 minutes, or until the ribs are tender and the vegetables are browned at the edges.
Remove from the oven and let rest for 5 minutes. Arrange the ribs on a platter to emphasize the skeleton shape and scatter the roasted vegetables around them. Sprinkle with fresh parsley before serving.