Laser Potato Bake

Preparation

Prep Time: 360min | Cook Time: 120min

1. Peel the potatoes. Set mandoline slicer to 1/16 inch and slice all the potatoes.
2. Trace the top of a ten inch cast iron skillet on parchment paper twice, and cut both out with scissors.
3. Preheat oven to 400 °F.
4. Thinly slice the onions, melt 12 Tablespoons of butter in a large pot over medium heat, and add onions to the pot.
5. Sweat the onions in the butter for about five minutes, remove from heat, and add the potatoes.
6. Toss the potatoes until well-coated in butter and onions are evenly distributed. Add salt and pepper to taste.
7. Place one of the circular parchment paper cutouts on the bottom of the skillet, and carefully add all of the ingredients to the skillet, building closely packed layers. Top with the remaining paper cutout and cover again with foil.
8. Bake for about 90 minutes, or until a thin skewer or long fork passes through the potatoes without resistance. You may wish to place a large baking sheet on the rack beneath the skillet, in case there is any overflow.
9. Set the oven to broil, remove the foil and parchment from the top of the dish, and broil uncovered for 10 minutes.
10. Allow to cool at room temperature, and then flatten gently with a broad spatula. Cover with plastic wrap and place in the refrigerator for at least five hours – overnight or longer if needed or desired.
11. When ready to eat, spread the remaining 3 Tablespoons of butter on a baking sheet and preheat the oven to 400 degrees.
12. Carefully remove the pie from the skillet by running a knife around the edges of the pan and overturning it on a cutting board. Slice it into twelve slices.
13. Transfer the pieces to the baking sheet and bake for about 10 minutes, until warmed through and browned. Serve immediately.