Preheat your oven to 375°F (190°C).
Peel and dice the Yukon Gold potatoes into uniform pieces.
Boil the potatoes in a large pot of salted water until fork-tender, about 15-20 minutes.
Drain the potatoes and return them to the pot over low heat.
Add the melted butter, heavy cream, sour cream, garlic powder, salt, and pepper to the potatoes.
Mash the potatoes until smooth, then fold in the cheddar cheese.
Transfer the mixture to a greased baking dish and smooth the top with a spatula.
Bake in the preheated oven for 25-30 minutes until golden and set.
Garnish with fresh chives before serving.
