How to Make It
Preheat the oven to 375°. Line a large heavy baking sheet with parchment paper and lightly brush the parchment with some of the butter. Using a mandoline, cut the potato crosswise into paper-thin slices. Spread about 24 of the slices (to get 18 perfect chips for assembling the towers) in a single layer on the parchment. Brush the potatoes with the remaining butter and season with salt and pepper.
Cover the potatoes with another piece of parchment and top with a second baking sheet. Bake for 25 to 30 minutes, or until evenly golden; rotate the baking sheet once during baking so the potatoes brown evenly. Transfer the chips to a tray lined with paper towels. Reduce the oven temperature 300°.
In a small bowl, stir the chives into the créme fraîche and set aside. Spread the scallop slices on a baking sheet and bake for 1 to 2 minutes, or just until they lose their transparency; they should still be rare.
To assemble the towers, place a potato chip in the center of each plate and top with 3/4 teaspoon of caviar, 1 scallop slice and a dab of the chive créme fraîche. repeat the layering once and top with a potato chip. Garnish with a large pinch of frisèe and serve at once.