Preheat your oven to 400°F (200°C). Spray a 9x13 inch baking dish with cooking spray or lightly oil it.
In a large mixing bowl, combine the halved baby potatoes, sliced sausage, olive oil, garlic powder, onion powder, paprika, salt, and pepper. Toss until everything is well-coated.
Spread the potato and sausage mixture evenly in the prepared baking dish.
Bake in the preheated oven for 30 minutes, stirring halfway through to ensure even cooking.
After 30 minutes, remove the dish from the oven and drizzle the ranch dressing over the top. Stir to combine.
Sprinkle the shredded cheddar cheese evenly over the potato and sausage mixture.
Return the dish to the oven and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let it cool for a few minutes. Garnish with chopped green onions if desired before serving.