Preheat the oven to 350F (171C). Melt 1 teaspoon of ghee: I put it in the cast iron dish and gently warmed it on the stovetop until the ghee was liquid, then turned the heat off and set the dish aside until I was ready to use it.
Halve, core, and thinly slice the apples. You want the slices to be somewhere around 1/16-inch thick. More than ⅛-inch and they will take a long time to soften. Use a sharp knife, and get in the zone! Your patience and precision will be rewarded.
Start laying the apple slices into the dish, slightly overlapping them. I did the outside circumference of the dish first, then did another circle inside that. You may have apple slices leftover...bonus snack!
Sprinkle the apple pie spice on top of the apples and dot the extra teaspoon of ghee over the top of the apples. You don't really need to do that, but I think it adds a nice buttery touch.
Bake for about 20 minutes, or until the apples have softened and begun to brown slightly at the edges.