In a large mixing bowl, make the cake batter per the instructions on the box.
Spray a 2 ½ quart baking dish with nonstick cooking spray. Pour the cake batter into the baking dish.
Using a spoon, scoop the frosting all over the top of the batter. This creates the gooey chocolate center while the cake cooks.
Place the lid on the baking dish. Microwave the molten lava cake for 10 minutes at full power.
Remove the cake from the microwave and let set, with the lid still on for another 5 minutes.
Remove the lid and dust with powdered sugar if desired. Serve the cake while still warm with either whipped cream or a scoop of vanilla ice cream.
Notes
*The nutritional information for this recipe was calculated using the Pillsbury brand cake mix and ingredients needed to make the cake, and Pillsbury tub of frosting. Follow the cake mix directions and use the ingredients needed per the instructions on your box or brand of cake mix. Cooking time may vary depending on the power of your microwave.