01 -
Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 -
Combine cubed sweet potatoes with olive oil and 1 teaspoon ground cinnamon in a large bowl, mixing to coat evenly. Arrange in a single layer on the prepared baking sheet and roast for 50 to 60 minutes, until tender and golden. Cool slightly.
03 -
Reduce oven temperature to 375°F. Lightly grease a 9x13 inch baking dish. Transfer roasted sweet potatoes to a large bowl. Add almond milk, vanilla extract, cubed butter, and brown sugar. Mash or blend until smooth and creamy.
04 -
Spoon sweet potato mixture into the prepared baking dish and spread evenly. Gently tuck in some marshmallows throughout the mixture for extra richness.
05 -
In a separate bowl, stir together pecans and maple syrup until nuts are well coated.
06 -
Sprinkle marshmallows and the maple-pecan mixture evenly over the casserole. Cover with foil and bake for 15 minutes at 375°F. Remove foil and bake an additional 15 minutes, until topping is golden brown and marshmallows are melted.