Preheat the Oven: Preheat your oven to 400°F (200°C).
Prep Sausage and Potatoes: Wash and cut the baby potatoes in half or quarters. Slice the smoked sausage into 1/4-inch thick rounds.
Combine Seasonings: In a small bowl, mix together the ranch seasoning, garlic powder, onion powder, and black pepper.
Coat Potatoes: Place the cut potatoes in a large bowl. Drizzle with olive oil and sprinkle with half of the prepared ranch seasoning mixture. Toss until evenly coated.
Assemble on Sheet: Line a baking sheet with parchment paper or lightly grease it. Spread the seasoned potatoes in a single layer.
Add Sausage: Scatter the sliced smoked sausage pieces evenly over the potatoes.
Roast: Place the baking sheet in the oven and roast for 35-40 minutes, or until the potatoes are tender. Stir the mixture halfway through cooking.
Add Cheese: Remove the baking sheet from the oven and sprinkle the shredded cheddar cheese over the potatoes and sausage.
Finish Bake: Return the dish to the oven and bake for an additional 5 minutes, or until the cheese is melted and bubbly.
Serve: Garnish with freshly chopped parsley, if desired. Serve hot with a dollop of sour cream.