Tip: Another recipe with the exact-same name "Mississippi Mud Cake " ranks higher.
The women of Huffman United Methodist Church in Birmingham used this recipe for the church's 125th anniversary celebration. Of the 100 cakes made, there wasn't any left over.
Whisk together melted butter and next 5 ingredients in a large bowl. Stir in flour and chopped pecans. Pour batter into a greased and floured 15- x 10-inch jellyroll pan.
Bake at 350° for 20 to 25 minutes or until a wooden pick inserted in center comes out clean. Remove from oven; top warm cake evenly with marshmallows. Return to oven, and bake 5 minutes. Drizzle Chocolate Frosting over warm cake. Cool completely.
Note: 2 (19.5-ounce) packages brownie mix, prepared according to package directions, may be substituted for first 7 ingredients. Stir in chopped pecans. Bake at 350° for 30 minutes. Proceed with marshmallows and frosting as directed.