For the cupcakes: Preheat the oven to 325 degrees F. Line standard-size cupcake pans with 16 cupcake liners.
In a medium bowl, melt the margarine in the microwave. Once melted, add in the can sugar, applesauce, soy milk, vanilla and lemon zest. Sift the flour, baking powder and salt into the wet mixture and whisk together until everything is evenly incorporated with few lumps remaining.
Fill the liners three-quarters full and bake until golden and a toothpick comes out clean, about 15 minutes. Cool completely.
For the berry filling: In a small bowl, combine the fruit with the cane sugar and lemon zest.
For the lemon buttercream: In the bowl of a stand mixer, cream together the vegetable shortening and margarine until light and fluffy. Add in the powdered sugar and lemon zest and continue to mix until it is fluffy.
To assemble: Poke a hole in the center of each cupcake using the end of a wooden spoon or small offset spatula. Fill the hole completely with the fruit filling. Using a large round frosting tip, pipe a generous amount of lemon buttercream.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.