1. Preheat Oven and Prepare Pan:

Preheat your oven to 350°F (175°C).

Grease a 13×9-inch baking dish thoroughly.

Sprinkle the miniature marshmallows evenly over the bottom of the greased dish. Set aside.

2. Prepare Strawberry-Gelatin Mixture:

In a bowl, combine the thawed frozen sweetened sliced strawberries (including their juice) and the dry strawberry gelatin powder.

Stir gently to combine. Set aside.

3. Make the Cake Batter:

In a large bowl, cream the shortening and the 1 ½ cups granulated sugar together with an electric mixer until light and fluffy, about 5-7 minutes.

Add the room temperature eggs, one at a time, beating well after each addition.

Beat in the vanilla extract.

In another bowl, whisk together the all-purpose flour, baking powder, and salt.

Gradually add the dry ingredients to the creamed mixture alternately with the milk, beginning and ending with the dry ingredients. Beat well after each addition until the batter is smooth.  

4. Layer the Cake:

Pour the cake batter carefully and evenly over the marshmallow layer in the baking dish.

Spoon the strawberry-gelatin mixture evenly over the cake batter. Do not stir the layers together.

5. Bake the Cake:

Bake in the preheated oven for 45-50 minutes, or until a toothpick inserted into the center of the cake layer (avoiding the strawberry topping) comes out clean.

6. Cool Slightly:

Let the cake cool in the pan on a wire rack for 10 minutes. Do not cool completely in the pan, or the topping may stick.

7. Invert the Cake:

Run a knife around the edges of the pan to loosen the cake.

Place a large serving platter over the top of the baking dish.

Carefully and quickly flip the baking dish and the platter together to invert the cake onto the platter. The strawberry-marshmallow layer will now be on top.

Lift off the baking dish. If any marshmallows stick, gently nudge them back onto the cake.

8. Cool Completely and Serve:

Let the inverted cake cool completely on the platter before slicing.

Garnish with fresh strawberries and whipped cream just before serving. Enjoy this fun twist!