Heat the oven to 400°F and pierce each potato several times with a fork.

Bake the potatoes directly on the oven rack for 45 to 50 minutes, until a knife slides into the center with no resistance.

Let the potatoes cool for 15 minutes, until they are comfortable to handle.

Slice each potato in half lengthwise and scoop out most of the flesh, leaving a 1/4-inch shell (save the scooped flesh for another use, like mashed potatoes).

Brush the inside and outside of each shell lightly with the bacon fat or a little oil, then return to the baking sheet.

Bake for another 10 minutes, until the shells crisp up and hold their shape when picked up.

Fill each shell with cheddar cheese and crumbled bacon.

Bake for a final 5 minutes, until the cheese is fully melted.

Top each skin with a small spoonful of sour cream and a scattering of chives, and serve warm.