Preheat the oven to 375 degrees F.
Place the potatoes on a baking sheet and cook the potatoes whole, do not pierce. Bake for 45 minutes to 1 hour. Lightly squeeze the potatoes - if they are soft, they are done. Let cool.
In a small saute pan over high heat, add the pecans and lightly toast. Add 4 tablespoons of butter, reduce the heat to medium, add the agave and spices, and allow to simmer for 4 to 5 minutes. Add the whiskey and continue to simmer for 5 minutes more.
Peel the potatoes and cut into 1/2-inch slices. Butter the bottom and sides of an 8 by 8-inch baking dish. Arrange the sweet potatoes, alternating with the apples. Pour the whiskey-pecan mixture over the top and place in the oven.
Bake for 30 minutes, basting the top with the whiskey sauce once at 15 minutes.
Remove and serve immediately.
Recipe courtesy of Guy Fieri