Step 1

Mix together the butter, brown sugar, cinnamon and vanilla extract together in a small bowl.

Step 2

Place the diced sweet potatoes in a 4-6 quart crock pot. Stir in the butter mixture and toss the sweet potatoes to coat the sweet potatoes in the butter mixture. Top it with the chopped pecans.

Step 3

Cover and cook on low for 7-8 hours or high for 3-4 hours until the potatoes are soft.

Step 4

Place the marshmallows on top for the last 10-15 minutes to softly melt the marshmallows.

Step 5

Serve it immediately and enjoy!