Preheat your oven to 400°F (200°C).
Wash and peel the Yukon Gold potatoes, then cut them into 1/2-inch cubes.
In a large mixing bowl, combine the cubed potatoes, olive oil, garlic powder, onion powder, salt, and black pepper. Toss until the potatoes are well coated.
Spread the seasoned potatoes evenly in the baking dish. Cover with aluminum foil.
Bake the potatoes in the preheated oven for 30 minutes. After 30 minutes, remove the foil and give the potatoes a good stir.
In a separate bowl, mix together the sour cream and milk. Pour this mixture over the potatoes, stirring to combine.
Sprinkle the shredded cheddar cheese evenly on top of the potatoes.
Return the uncovered baking dish to the oven and bake for an additional 15 minutes, or until the potatoes are tender and the cheese is bubbling and golden brown.
Once cooked, remove from oven and let it cool for a few minutes. If using, sprinkle chopped green onions on top for garnish before serving.