Preheat oven to 350°. Place potatoes on a aluminum foil lined baking sheet. Bake for about 1 1/2 hours, until very tender. Cool 30 minutes. Peel and discard potato skins.

Stir together the potatoes, shallots, milk, eggs, sage, nutmeg, 1/2C melted butter, 2 tsp salt and 1 tsp of pepper with a fork until mostly smooth. Pour mixture into a lightly greased 9"×13" baking dish.

Combine pecans, breadcrumbs, cheese, remaining 1/2C butter, 1/2 tsp salt and 1/4 tsp pepper in a medium bowl. Sprinkle pecan mixture over potato mixture in an even layer.

Bake, uncovered until topping is golden brown, about 28-30 minutes. Sprinkle with parsley.