Make the Pureeclean the berries and slice them mix them with a TBSP of water, the sugar, and the lemon juice
cook over medium heat and crush with a wooden spoon or potato masher until almost smooth
cook until reduced to 1/2 cup of puree
cool until ready to use
To make the Cake: preheat the oven to 350° grease 2 9-inch round cake pans, then line the bottom with parchment paper, set aside
In a large mixing bowl, whisk together the cake flour, baking powder, salt, and baking soda
In the bowl of an electric mixer, beat the room temperature butter and sugar until light and fluffy, about 2-3 minutes-scrape down the sides of the bowl as needed
Beat in the egg whites on medium speed, scraping down the sides of the bowl after. The mixture should be light in color, fluffy, and creamy looking now
Add the sour cream and vanilla extract and beat until combined-scrape down the sides of the bowl
Add the flour mixture to the butter mixture, and mix on low speed until just barely combined-do not overmix
Slowly pour in the milk and mix until just combined
Stir in the ½ cup of the cooled strawberry puree (and optional food coloring) and mix until just barely combined
Pour evenly into the prepared pans and smooth the tops
Bake in the preheated oven for 20-25 minutes, until the cakes are golden on top, do not jiggle when the pan is wiggled, and a toothpick inserted into the center comes out clean
Cool the cakes in the pan on a wire rack until cool to the touch
Carefully turn the cake pans over and remove the cakes from the pan. Remove the parchment paper circles and place the cakes back on the wire racks to cool completely before frosting
To make frosting: in the bowl of an electric mixer fitted with a whisk attachment, beat together the softened butter and the vegetable shortening until light and fluffy, about 3 minutes
Slowly add in the powdered sugar, 1 cup at a time, scraping down the bowl as needed, until the frosting is creamy and combined
Add in the vanilla and salt and beat until combined
Mix in the milk until combined and you have a nice, creamy, fluffy frosting
To Assemble: Place one cooled cake round on a cake stand
Place half of the frosting onto the cake round
Evenly spread the frosting over the cake, ensuring that you take it all the way to the edges and overhanging the edge just a little
Place the second cooled cake circle on top
Add the remaining frosting to the top of the cake
Evenly spread the frosting over the top of the cake
Use a bench scraper or icing spatula to smooth out the frosting on the sides of the cake
Refrigerate the cake for 2 or 3 hours to allow the frosting to set before slicing and serving
Decorate the top of the cake with whole and sliced strawberries as desired
Serve within several hours or store covered with plastic wrap in the fridge
If your store it in the fridge allow it come to room temperature before serving