Line a baking sheet with foil and preheat the oven to 425 degrees.

Wash and dry sweet potatoes and prick all over with a fork. Place on baking sheet.

Rub sweet potatoes all over with vegetable oil and sprinkle with kosher salt.

Roast for 40-45 minutes until a fork easily pokes into the center of the potatoes.

Remove from oven and allow to cool for 20-30 minutes or until cool enough to handle.

Cut a slit in the top of each sweet potato and carefully scoop out the inside leaving a bit to support the skins.

Place scooped sweet potato in a bowl and add 6 tablespoons butter, ¼ cup maple syrup, 1 teaspoon salt, cinnamon, and nutmeg.

Whip with an electric mixer until fluffy and smooth.

Spoon filling back into shells.

Melt remaining 4 tablespoons of butter in a small saucepan over low heat.

In a small bowl combine oats, pecans, brown sugar, and flour. Pour melted butter over the top and toss with a fork to combine.

Top sweet potatoes with crumble mixture and dot with mini marshmallows if desired.

Return to oven and bake an additional 15-20 minutes to brown up the topping.

Serve warm.