Are you talking about momsrule's buckeye cake? I have never had any problems with it~
Is this the recipe you were referring to? If it is, I don't know what to say to help you other than to pour it when it is still warm and 'gooey'
Linda
Buckeye Cake
First Layer
1 box, (2-layer size)
Devil's Food cake mix
1-1/3 cups water
1/2 cup vegetable oil
3 eggs
Second Layer
2 cups sugar
1/2 cup milk
1-1/3 cups smooth peanut butter
1 jar (7 oz.) marshmallow crème
Third Layer
1 stick (1/2 cup) butter
1/4 cup Hershey's cocoa
1/3 cup milk
1 lb. confectioners' sugar
1/4 tsp. vanilla
Grease and flour a 15 X 11-inch jellyroll pan. Preheat
oven to 350.
First layer: Prepare cake as directed on box, using water, oil, and eggs for the ingredients.
Pour mixture into pan. Bake 20-22 minutes or until
toothpick inserted comes out clean. Cool
completely, Second layer: In a saucepan, bring sugar and milk to a boil. Boil 3 minutes. Add peanut butter and marshmallow crème; mix well. Quickly pour on top of cooled cake.
Spread evenly. Cool completely.
Third layer: In a medium saucepan, melt butter, cocoa and milk together. Bring to a boil.
Remove from heat and add confectioners' sugar and
vanilla. Stir completely. Pour icing on top
of cooled peanut butter layer.
Cool completely before cutting.