Originally posted in a comment at The Bus o' Love, reposted here because Ms. Huis Herself asked me to. I don't remember where I got this one.
Au Gratin Potatoes
Preheat oven to 400°
3 lbs. thinly sliced red potatoes
1 1/4 cups creme fraiche
1 1/4 cups shredded gruyere, shredded
Salt, pepper & paprika to taste
parsley or crushed rosemary
Generously butter a 9x13 cake pan. Add in layers: half of the potatoes, half the creme fraiche, and half of the cheese, add salt, pepper and paprika. Repeat. Bake 45 minutes. Before serving, sprinkle parsley or crushed rosemary over the top.