Prep Work

1. Preheat oven to 350°F and grease a 9×9-inch baking dish with butter.

Cook the Sweet Potatoes

1. Wash and cook sweet potatoes using your preferred method:
   1. Stovetop method: Bring large pot of water to boil, add whole sweet potatoes, cook 20-30 minutes until fork-tender
   2. Instant Pot method: Add sweet potatoes with water to cover, high pressure 10 minutes, quick release
   3. Oven method: Poke with fork, bake at 400°F for 45-60 minutes until soft Cool and peel the sweet potatoes once tender. Let cool slightly before handling.

Make the Soufflé Base

1. Mash sweet potatoes in large mixing bowl until completely smooth and silky. 
2. Add wet ingredients: Whisk in eggs, heavy cream, brown sugar, softened butter, vanilla, and salt.
3. Beat until fluffy: Use hand mixer or stand mixer to beat mixture until light and airy, about 3-4 minutes.

Prepare the Topping

1. Make cinnamon crumb topping: In separate bowl, combine flour, brown sugar, and cinnamon. Cut in softened butter with fork or pastry cutter until mixture forms small crumbs.

Assemble and Bake 

1. Assemble soufflé: Pour sweet potato mixture into prepared baking dish, spreading evenly.
2. Sprinkle crumb topping over entire surface.

Bake:

1. Bake 45-50 minutes until top is golden brown and center is set (knife or toothpick inserted in center comes out clean). Serve immediately while soufflé is at its fluffiest!