Preheat oven to 400°F (200°C).
In a large bowl, toss potatoes, onions, olive oil, garlic powder, paprika, salt, and pepper until well coated.
Spread the potato mixture evenly on a baking sheet and bake for 20 minutes.
Add the sliced smoked sausage to the baking sheet, stir, and bake for an additional 20 minutes or until the potatoes are tender.
Sprinkle shredded cheddar cheese over the mixture and return to the oven for 5 minutes, or until the cheese is melted.
Garnish with chopped parsley and serve hot.