To bake sweet potatoes:  

Wash and dry and poke all over with a fork.  Place directly on the baking rack or a foil-lined baking sheet and bake for 1 hour at 400 degrees, or until tender when pierced with a knife.  Allow to cool, peel and mash.  This can be done a day or two ahead of time.  

Air Fryer: It takes almost the same amount of time, but you don’t have to heat your big oven.  Rub with a little bit of oil and bake at 380 degrees for 45-55 minutes, depending on size.  

To bake the souffle:

Preheat oven to 350 degrees.  

Mix mashed sweet potatoes and all other ingredients in a food processor or with a hand mixer at high speed.  

Butter a small casserole dish.  Place the souffle mixture in the dish, smoothing top.  

Mix topping ingredients and sprinkle evenly over the surface of the casserole.  

At this point, you could cover and refrigerate for up to 24 hours ahead.  Allow it to come to room temperature before baking.  

Bake for 40 minutes or until it starts to bubble almost all the way through.