Preheat the oven to 400 degrees Fahrenheit.
Scrub the sweet potatoes and pat dry. Add to a baking sheet lined with foil and bake for about an hour or until easily pierced with a fork.
Remove from the oven and let cool until easy to handle.
Combine the oats, coconut sugar, flour, pecans, and oil in a bowl and mix together. Set aside.
Once the potatoes are done, peel the skin off and transfer to a large bowl and roughly mash with a potato masher.
Lower the oven temperature to 350.
Add in all remaining ingredients and beat with an electric mixer until smooth, OR add to a food processor and process until smooth.
Transfer to a 9x9 baking dish and spread evenly.
Sprinkle on top the oat crumble. Bake for 10 minutes, then remove from the oven and top with marshmallows.
Bake for an additional 15-25 minutes or until the tops of the marshmallows are golden brown. Serve warm and enjoy!