Preheat the oven to 400ºF. Place the sweet potatoes on a baking sheet and prick each potato in several places with a fork. Bake for about 1 hour or until tender when pierced with a knife.

When cool enough to handle, scoop the potato flesh into a food processor fitted with the steel blade. Add the butter, applesauce, cinnamon, ginger, nutmeg, and salt and pepper, to taste. Puree until smooth. (Depending on the size of your food processor, this may need to be done in batches.) Transfer to a casserole dish. Top with the nuts.

Return to the oven for about 15 minutes or until warmed through and the nuts are lightly browned. Serve warm.

To make ahead: Prepare the casserole up to the point of topping with the nuts. Cover and refrigerate for up to 3 days. To reheat, add an extra 10 minutes onto the baking time. Cover with foil if the nuts brown too quickly.