Chocolate Malt Treasure Cake

2 cups Softasilk cake flour
2 cups granulated sugar
1/2 cup shortening
3/4 cup water
3/4 cup buttermilk
1 teaspoon salt
1 teaspoon baking soda
1 teaspoon vanilla extract
1/2 teaspoon baking powder
2 eggs
4 ounces unsweetened baking chocolate, melted and cooled

Malt Treasure Filling
2 cups powdered sugar, sifted
1 cup Marshmallow Cr