Strawberry Shortcake Cake

Preheat the oven to 350 degrees F (175 degrees C). Grease and flour three 10-inch cake pans.

Beat egg whites in a bowl for 1 minute; set aside.

Sift flour, sugar, baking powder, and salt together into a bowl. Add shortening and 1/2 of the milk; mix well. Add remaining milk, egg whites, and vanilla extract. Mix well. Pour into the prepared pans.

Bake in the preheated oven until a toothpick inserted into the centers comes out clean, about 30 minutes. Let cool in the pan for 10 minutes, then remove cake and let cool completely on rack, about 30 minutes.

While cake layers cool, mash strawberries in a large bowl; add sugar. Refrigerate filling in a covered container for at least 30 minutes.

Trim tops off the cake layers to level and to remove as much crust as possible. This allows the strawberry filling to soak into the cake.

Liberally spread strawberry filling on top of a cake layer, without running over the sides. Add another cake layer. Spread more filling. Repeat with the last layer.

Put a circular plastic container upside down over the strawberries on top; spread whipped topping around the rim. Remove the container to reveal the strawberries in the center.