Preheat oven 400F
butter a 2 quart casserole pan or baking dish
heat oil in large skillet. Add onions, tender, golden, 10 minutes.
Add garlic; stir 1 minute. Add cream, broth, rosemary, salt and pepper. Remove
from the heat.
Mix all cheeses in a bowl.
Mix potatoes in a bowl.
Arrange 1/3 of the potatoes on the bottom of the dish. Sprinkle 1/3
cheese. Repeat twice more, ending with a cheese layer. Pour the cream mixture
over the layers, cover with foil, bake 45 minutes.
Remove foil, bake another 20-25 minutes until golden. Remove, let rest, sprinkle
with parsley.