Preheat oven to 350°F. Line two large baking sheets with parchment paper and set aside.
In the bowl of a mixer, combine cake mix, eggs, oil, and water. Mix on medium low speed until combined.
Place small spoonfuls of batter (I used a very small cookie scoop) on lined baking sheet, several inches apart — they spread a lot!!
Bake for about 7 minutes, until edges are set and centers spring back when lightly touched.
Remove from oven and let cool on baking sheet for a few minutes. Remove to wire rack to finish cooling.
In a metal mixing bowl set over a pot of simmering water on the stove, whisk together egg whites and sugar until sugar seems to have melted and the mixture forms a syrup, about 10 minutes.
Remove from stove and set bowl on your mixer. Beat on high with the whisk attachment until it forms stiff peaks, about 10 minutes.
Using a large open-star tip, pipe marshmallow frosting on each cookie.
In a microwave-safe bowl, heat chocolate chips and vegetable oil for 2 minutes, stopping to stir every 20 seconds until chips are melted and mixture is smooth.
Spoon over frosted cookies, then immediately sprinkle with graham cracker crumbs.