Set griddle on low
Cut sweetpotatoes into small pieces and place into a large bowl
Add olive oil, pepper and salt. Stir to mix together or cover it with a lid and shake.
Add sweetpotatoes to the griddle. Once they develop a bright color and have softened, make an empty circle inside the sweet potatoes and add unsalted butter
Once butter is melted, add brown sugar. Once the brown sugar pulls together with the butter, mix all ingredients. After everything is combined, let it cook for a few minutes
When done, place in an aluminum pan and cover the top with marshmallows
Use a culinary torch to give a nice brown color all the way across the top or place in oven at 350 degrees for a few minutes to get desired color