Preheat oven to 425 degrees F.

Melt the butter, and saut? the onion over medium heat until soft and translucent. Add the garlic, salt, and pepper and cook for about 30 seconds.

Add the stock, cream, and potatoes and bring to a good simmer. Cover, reduce heat to medium-low and simmer gently until the potatoes are nearly tender when pierced with a knife, about 15 to 20 minutes. Taste and adjust seasoning to your taste. Gently stir.

Transfer the mixture to a buttered 8 x 8? or equivalent sized baking dish. Top with the cheese and bake in the preheated oven for about 10 -15 minutes or just until the sauce is bubbling and the cheese is melted. Cool a few minutes before serving. Sprinkle with chopped parsley.