Step 1

Preheat oven to 375 degrees.

Step 2

Place sweet potatoes in large dutch oven and cover with water. Bring to a boil and cook until fork tender.

Step 3

Meanwhile, in a small bowl, stir together flour, brown sugar and salt. Using two forks or a pastry blender, cut butter into flour mixture until it resembles coarse crumbs.

Step 4

Stir pecans into flour mixture.  Set bowl aside.

Step 5

Drain potatoes and transfer to the bowl of an electric mixer.

Step 6

Add half and half, brown sugar, salt and vanilla. Beat until smooth and combined.

Step 7

Add eggs and beat until well combined.

Step 8

Pour sweet potato mixture into greased 9x13 baking dish.

Step 9

Sprinkle marshmallows evenly over sweet potato mixture.

Step 10

Sprinkle streusel evenly over marshmallows.

Step 11

Bake casserole for 30-35 minutes or until marshmallows are golden brown or desired color.

Step 12

Casserole may be served immediately or allowed to sit at room temperature up to four hours prior to serving.