Method:

• Heat oven to 350ºF for shiny metal or glass pan (or 325oF for dark or nonsick pan). Grease bottom only of 13x9-inch pan with shortening or nonstick cooking spray. In large bowl, beat cake mix, cracker crumbs, water, oil and eggs with electric mixer on low speed 30 seconds. Beat on medium speed 2 minutes. Pour into pan.
• Reserve 1/4 cup hot fudge topping. Drop remaining hot fudge topping by generous tablespoonfuls randomly in 12 to 14 mounds onto batter in pan.
• Bake 40 to 46 minutes or until toothpick inserted in center comes out clean. Run knife around side of pan to loosen cake. Cool 15 minutes.
• Spoon teaspoonfuls of marshmallow creme onto warm cake; carefully spread with knife dipped in hot water. Drop small dollops of reserved hot fudge topping randomly over marshmallow creme. Swirl topping through marshmallow creme with knife for marbled design. Cool 2 hours. Store uncovered at room temperature. (Once cut, store cake in the pan, uncovered, with plastic wrap pressed against cut sides.)