Giant Hostess Cake Swiss Roll

Name: Giant Hostess Cake Swiss Roll
Cook time: 55 min
Total time: 55 min
Cuisine: European
Ingredients: 1/4 cup cocoa powder; 1/3 cup flour; 1/4 tsp salt; 1 tsp baking powder; 1/2 tsp instant coffee; 4 eggs; 1/2 cup sugar; 1 stick butter; 1/4 cup vegetable shortening, such as Crisco; 7 oz marshmallow fluff, such as Jet Puff; 1 tsp vanilla; 1 cup powdered sugar; Dark chocolate, melted; Hostess Swiss Rolls for decoration