Preheat the Oven to 400°F (200°C).
Wash and halve or quarter the baby potatoes.
Slice the smoked sausage into 1/4-inch thick rounds.
In a small bowl, mix ranch seasoning, garlic powder, onion powder, and black pepper.
Place potatoes in a large bowl, drizzle with olive oil, add half the seasoning mix, and toss to coat evenly.
Line a baking sheet with parchment paper or grease lightly.
Spread the potatoes in a single layer on the sheet.
Scatter sliced smoked sausage evenly over the potatoes.
Roast in the oven for 35-40 minutes, stirring halfway through.
Remove from oven and sprinkle shredded cheddar cheese over the potatoes and sausage.
Return to oven and bake 5 more minutes until cheese is melted and bubbly.
Garnish with chopped fresh parsley and serve hot with optional sour cream.