Let’s bake this exciting Upside-Down Strawberry Shortcake! It’s all about careful layering and that final flip. First, preheat your oven to 350°F (175°C). Grease your 13×9-inch baking dish very thoroughly – don’t miss the corners!

Sprinkle the 1 cup of miniature marshmallows evenly over the bottom of the greased pan. Set it aside for a moment.

In a separate bowl, combine the thawed package (16 ounces) of frozen sweetened sliced strawberries (including their juice) with the dry powder from the 3-ounce package of strawberry gelatin. Stir them together gently until the berries are coated. Set this mixture aside.

Now, make the cake batter. In a large bowl, cream the 1/2 cup shortening and 1 1/2 cups sugar together with an electric mixer on medium speed until light and fluffy. This takes a good 5 to 7 minutes and incorporates air into the batter.

Add the 3 room temperature eggs one at a time, beating well after each addition until fully incorporated. Beat in the 1 teaspoon of vanilla extract.

In another bowl, whisk together the 2 1/4 cups all-purpose flour, 3 teaspoons baking powder, and 1/2 teaspoon salt.

Add the dry ingredients to the creamed mixture alternately with the 1 cup of milk, beginning and ending with the dry ingredients. Mix on low speed after each addition, beating just until combined. Don’t overmix!

Carefully pour the finished cake batter evenly over the marshmallows in the prepared pan. Spread it gently to cover them.

Spoon the strawberry-gelatin mixture evenly over the top of the cake batter. Don’t worry about swirling it in; just distribute it over the surface.

Place the pan in the preheated oven. Bake for 45 to 50 minutes, or until a wooden toothpick inserted into the center of the cake layer (avoiding the gooey topping) comes out clean. The cake should be golden brown and spring back lightly when touched.

Once baked, carefully remove the pan from the oven and place it on a wire rack. Let the cake cool in the pan for exactly 10 minutes – no more, no less! This allows it to set slightly but keeps the topping warm enough to release.

After 10 minutes, run a knife carefully around the edges of the pan to loosen the cake. Place your large serving platter upside down over the top of the baking dish. Taking a deep breath and holding both the platter and the hot pan firmly (use oven mitts!), quickly and confidently flip them over together.

Carefully lift off the baking dish. If some topping sticks, gently coax it out with a spatula and patch it onto the cake. Let the inverted cake cool completely on the wire rack before garnishing.

Once cool, garnish generously with fresh strawberries and dollops of whipped cream. Slice and serve!