Chocolate, marshmallow, and graham crackers never tasted better! This take and bake cake serves 16, so it's definitely one you'll want to bring to your next party.
Preheat oven to 350°F. Grease a 13x9-inch baking pan. In a medium bowl stir together graham cracker crumbs and the 1/3 cup sugar; stir in melted butter. Press crumb mixture firmly into bottom of pan.
In a bowl stir together the next five ingredients (through salt). In a large bowl beat softened butter with a mixer on medium 30 seconds. Add the 2 cups sugar, 1/4 cup at a time, beating on medium until combined. Scrape bowl; beat 2 minutes more. Add eggs, one at a time, beating after each. Beat in vanilla. Alternately add flour mixture and milk, beating on low after each addition just until combined. Beat on medium to high 20 seconds more. Spread batter over crumb mixture in pan.
Bake about 50 minutes or until a toothpick inserted in center comes out clean. Cool in pan on a wire rack. Spread cake with Marshmallow Frosting. If desired, sprinkle with additional graham cracker crumbs.
Use packaged graham cracker crumbs or make your own. Twenty-four full graham crackers (48 squares) pulverized in a food processor yields 3 cups.
In a large bowl beat butter with a mixer on medium 30 seconds. Beat in marshmallow creme and vanilla just until combined. Gradually add powdered sugar, beating just until combined.