• Heat the oven to 425°F for a standard metal muffin tin or 400°F for a cast-iron muffin pan. Thoroughly coat six muffin cups with a thin layer of beef tallow or softened butter.

  Scrub the potato and slice it very thinly and evenly with a mandoline.

  Separate the potato slices and place them in a bowl. Add the melted butter, Parmesan, salt, pepper, and thyme. Toss well, making sure the slices are evenly coated.

  Divide the potato slices among the six prepared muffin cups, stacking them tightly and slightly above the rims. The stacks will settle as they bake.

  Bake for 30–40 minutes, or until a thin knife slides easily through the center and the tops, edges, and bottoms are golden brown.

  Allow the potato stacks to rest in the pan for 5 minutes. Run a thin knife around the edges and remove them while they are still warm.

Notes

• These potato stacks can be made earlier in the day or up to one day ahead. Let them cool completely, then refrigerate in an airtight container. To serve, arrange them on a sheet pan and reheat in a 375°F oven for about 10–15 minutes, or until hot and crisp around the edges.

Notes

• Slice the potato about ⅛ inch thick or slightly thinner. Even slices are important so the stacks cook at the same rate.

  One large baking potato should make six stacks, but the exact yield will depend on the size of the potato and muffin cups.

  Use 425°F for a standard metal muffin tin. If using a cast-iron muffin pan, reduce the oven temperature to 400°F.