Magical French Potato Cake

Directions

1. To make Garlic Creme Fraiche, put two cups of heavy cream into a pan on on the stove and add the crushed garlic clove. Cook over very low heat until cream is just warmed. Remove garlic clove. Cool cream and put into a clean jar. Add buttermilk and stir until combined. Leave on your counter for 12-24 hours until creme is thick, then cover and refrigerate for 7-10 days.
2. Peel potatoes and slice thinly, approximately 1/8 inch. A mandolin is very helpful. In a buttered pie plate or casserole dish, arrange slices until the bottom of the plate is covered. Spread 1-2 TB of creme fraiche over potatoes. Finely grate 1-2 oz gruyere (or emmenthaler) cheese and 1/2 TB thyme and sprinkle over the creme fraiche. Season with sea salt and white pepper (no pesky black spots when you use white pepper!)
3. Repeat process once more until you finish the last layer of potatoes. Cover the potatoes with plastic wrap. On top of the plastic, place a pan or a heavy dish and add cans to weigh the potatoes down. Refrigerate for 6-12 hours.
4. Preheat oven to 375 degrees. Remove cans and weights. Cover the potatoes with 3/4 to 1 cup of creme fraiche. You could add 1/2 to 1 cup heavy cream or 1/2 and 1/2 to the creme fraiche to reduce the richness of the dish. Sprinkle with the remainder of the thyme and grated gruyere cheese.
5. Put in the oven for 20-30 minutes - be careful not to let the dish burn. The creme fraiche will make a delicious brown crust around the edges.
6. After 30 minutes, reduce heat to 350 degrees and cover pie pan with foil. Cook another 30 minutes or until potatoes are tender. Carefully remove foil and let the potato pie cool until it can be cut into wedges.
7. I have cooked this and refrigerated it, heated it until warm, then cut it into wedges. It's even more "cakelike". It's an ideal do-ahead recipe, great for the holidays. Use the pan size you want and adjust the ingredient amounts accordingly.