Serves 4–8 as an appetizer or first course

1 cup heavy cream 

Coarse salt and freshly ground black pepper 

4 pounds sweet potatoes (3–4 large sweet potatoes) 

1–2 tablespoons unsalted butter, softened 

4 tablespoons unsalted butter, cut in cubes, kept cold 

2 tablespoons grapeseed oil 

⅓ cup creme fraiche or sour cream 

1 jar caviar of your choice, available at fish counter of many grocers 

Minced fresh chives 

Preheat oven to 350°F. 

Pour cream into a large bowl and season with 1 teaspoon salt and ½ teaspoon pepper. Remove the skins of the sweet potatoes using a knife, and trim all sides to create a rectangle shape. Set a mandoline over the bowl of cream and, starting with the long flat side of the potato, slice the potato lengthwise into very thin slices. Make sure the slices are coated in the cream as you go. 

With half the softened butter, coat the inside of a 9- by 5- by 3-inch loaf pan. Line the pan with parchment paper, leaving a 5-inch overhang on all sides. Coat the parchment paper with remaining softened butter and sprinkle with salt and pepper. 

Start by putting an even layer of sweet potato in the bottom of the loaf pan; repeat the process to form a second layer. Dot with a few cubes of the cold butter; season with light salt and pepper. Continue layering potatoes and adding butter and seasoning after every two layers until potatoes are gone, or the pan is filled. Fold sides of parchment paper over potatoes. Cover the pan tightly with aluminum foil and transfer to the oven. 

Bake until potatoes are tender when pierced with the tip of a sharp knife, about 40–45 minutes. Ovens vary, so if your oven runs high or you cook on convection, start checking for doneness at around 30 minutes. When done, remove from the oven and let cool for 15 minutes. Place another loaf pan on top of the aluminumcovered potatoes. Add some weights, such as a couple of cans, to compress and let potatoes cool to room temperature. Remove weights and tightly wrap the pan. Refrigerate potatoes for at least 6 hours or up to 48 hours. 

To serve, run an offset spatula between the parchment paper and pan to release. Using the parchment paper overhang, carefully lift the pave out of the pan or invert onto a cutting board. Trim sides of pave and cut into equal pieces approximately 2 inches square. Let stand at room temperature for 30 minutes so that the interior is not cold. 

Heat a large skillet over medium heat and add enough grapeseed oil to coat the bottom of the pan. When oil is hot, add potatoes, cut side down. Cook until browned on the first side, 1–2 minutes. Carefully turn and repeat on opposite side so both sides are caramelized. 

Transfer potatoes carefully to a serving platter. Place a small dollop of creme fraiche (or sour cream) and top with caviar. Finish with a sprinkle of chives. Serve.