Cook the sweet potatoes in an Instant Pot for 15 minutes on high pressure with 1 cup of water, then perform a quick release. Or bake in an oven preheated to 425°F for 45-50 minutes until fork-tender.

Prepare the pecan topping by mixing chopped pecans with brown sugar, dairy-free butter, and cinnamon until crumbly.

Mash the peeled sweet potatoes in a large bowl, then blend in dairy-free butter, brown sugar, gluten-free flour, and cinnamon.

Grease a 9x13-inch baking dish, pour in the sweet potato mixture, and spread evenly.

Sprinkle the pecan topping over the sweet potato mixture, then bake in a preheated oven at 350°F for 35-40 minutes.

Let the casserole cool for 10 minutes before serving.