Place the crushed strawberries into the bottom of a 9x13 inch baking pan.
Evenly sprinkle the dry gelatin powder over the strawberries.
Layer the miniature marshmallows on top of the gelatin powder.
Prepare the yellow cake mix following the instructions on the package.
Carefully pour the cake batter over the marshmallows.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 40 to 50 minutes.
Let the cake cool in the pan for 15 minutes.
Run a knife around the edges of the pan to loosen the cake.
Turn the cake out onto a serving tray.
Store the cake in the refrigerator.
Notes
Tips and Tricks
Use crushed strawberries - Crush the strawberries well before adding them. This helps the fruit layer spread more evenly across the cake.Sprinkle the gelatin evenly - Cover the strawberries with the dry gelatin powder as evenly as you can. This helps the strawberry topping set better after baking.Spread the marshmallows in one layer - Keep the marshmallows in an even layer so they melt into the strawberry mixture without clumping in one spot.Pour the cake batter slowly - Add the cake batter slowly over the marshmallows. This helps keep the layers from shifting too much.Check the center before removing from the oven - Insert a toothpick into the center of the cake. The cake is done when the toothpick comes out clean.Let the cake cool before turning it out - Let the cake cool for 15 minutes before turning it onto a serving dish. This helps the topping settle and makes the cake easier to release.Loosen the edges - Run a knife around the edges before turning the cake out. This helps the sides release cleanly.
How to Store
Refrigerate - Store Upside Down Strawberry Marshmallow Cake in the refrigerator. Cover it tightly with plastic wrap or place slices in an airtight container.Serve Chilled - Serve the cake chilled for the best texture. The strawberry topping holds better after it has time to cool in the refrigerator.Use Within 3 Days - Use the cake within 3 days for the best taste and texture. The topping may soften the cake more as it sits.