1 (18.25 ounce) package yellow cake mix
1/2 cup boiling water
2 eggs
1 (3 ounce) package instant chocolate pudding mix
3 fluid ounces lemon-lime flavored carbonated beverage
1/4 cup white sugar for garnish
Preheat the oven to 350 degrees F (175 degrees C). Grease a 9 inch square pan. Stir together cake mix, boiling water, eggs and pudding mix until blended. Stirring occasionally, stir the lemon-lime soda into the mix so that it does not clump.
Pour mixture into prepared pan. Carefully drop 2 tablespoons of the marshmallow mixture into the center of each pan. Place remaining marshmallow mixture over the filling and spread taco shape.
Bake in preheated oven for 60 minutes, or until filling is bubbly. Mix with lemon-lime soda before serving.