Preheat your oven to 400°F (200°C).
In a large bowl, combine the halved baby potatoes, sliced smoked sausage, ranch seasoning mix, garlic powder, onion powder, olive oil, salt, and pepper. Toss until everything is evenly coated.
Spread the mixture in a single layer on a large baking sheet lined with parchment paper.
Bake in the preheated oven for 25-30 minutes, or until the potatoes are tender and golden brown, stirring halfway through.
Remove from the oven and sprinkle the shredded cheddar cheese over the top. Return to the oven for an additional 5 minutes, or until the cheese is melted and bubbly.
Drizzle the sour cream over the dish before serving and garnish with chopped green onions if desired.