Rice cereal gives these soft chocolate cookies just the right amount of crunch.
Heat oven to 350 degrees F. Butter and flour 2 large light-colored baking sheets (not nonstick).
Place cake mix, cocoa, water, butter and eggs in large bowl. On low speed, beat until combined, 1 minute. On medium, beat 2 minutes. Add cereal. On low, beat just until combined. Lightly stir in marshmallow topping, leaving mixture marbled. Refrigerate, covered, 15 minutes.
Using greased tablespoon, spoon slightly heaping tablespoons of dough, about 2 inches apart, onto prepared baking sheets. Refrigerate remaining dough in between batches.
Bake in 350 degree F oven for 13 to 14 minutes, until puffed and set in center. Let cool on baking sheet 1 minute. With metal spatula, carefully remove cookies to rack. Let cool.
Clean baking sheets. Butter and flour sheets; repeat with remaining dough. Makes 3 dozen cookies.