Heat oven to 400ºF (200ºC). Peel the potatoes then use a mandolin to thinly slice them.
Bring a large pot of salted water to a boil over medium high heat. Add the potatoes and par-boil them until just tender but not falling apart, about 6 minutes.
Drain the potatoes place in a large mixing bowl. Add the cream, 1½ cups (337g) of the Cheddar cheese, 2½ (7g) tablespoons of the chives, onion powder and garlic powder, gently folding to combine. Season with salt and pepper and fold once more.
Grease a jumbo 6-cup muffin tin with butter. Divide the potato mixture among the muffin tin cups. Pour any extra cream left in the bowl over the potatoes. Top with the remaining cheese.
Bake until tender and the cheese is bubbling, about 15 to 20 minutes. Remove and let cool for 5 minutes, then run a knife around each of the cups of potatoes and gently lift them out.
Serve warm garnished with the remaining chives.
Notes
Par-boil. I slice the raw potatoes and drop them into boiling water to par-boil them so they are already tender.
Muffin tins. I then mix them with cheese, cream and spices before adding them to greased muffin tins. Adding to muffin tins allows for smaller individual portions as well as smaller surface area to cook in comparison to a larger baking dish.