To make strawberry puree, place a handful of fresh or frozen strawberries in a blender and puree until smooth. Divide into 1/4 cup for the cake and 1/2 cup for the buttercream.
Preheat the oven to 350 degrees F. Prepare three 8 or 9-inch nonstick cake pans. I recommend spraying a tiny bit of baking spray in the bottom of each pan, then line each one with parchment rounds. You can use butter and flour if you prefer, but don't grease the sides. Set aside.
In a medium bowl, combine the puree, milk, vanilla, and orange juice. In a separate large bowl, whisk together the flour, cornstarch, baking powder, salt and zest.
In a stand mixer fitted with the paddle attachment, cream the butter and sugar on medium-high until light and fluffy, 3-5 minutes. Scrape down the sides of the bowl. Turn down the speed to low and add the eggs, one at a time, scraping down the side of the bowl after each egg.
Swiftly alternate between adding the dry and wet ingredients, beginning and ending with the dry. Scrape down the bowl once more to ensure there are no dry patches.
Divide the batter evenly between the cake pans. Spread the tops evenly with a small offset spatula.
Bake for 20-25 minutes, or until a toothpick comes out clean.
Allow the cakes to cool for several minutes in the pan. Carefully invert onto cardboard cake rounds lined with parchment. Allow to cool completely. Once cool, you can wrap the cakes well in plastic wrap and store them at room temperature for two days, the refrigerator for five days, or the freezer for several months.
For the Buttercream
Add sugar, water and corn syrup (if using) to a medium sauce pot; do not stir. Cover, and turn the heat to high.
While the sugar is coming to a simmer, whisk the eggs on high in a stand mixer with the whisk attachment. Remove the cover from the sauce pot after some steam has formed. Cook the sugar to the soft boil stage, 235-240 degrees F.
Turn the mixer speed down to medium and slowly pour the syrup down the side of the bowl. Once the syrup is incorporated, turn the speed up to high and allow the meringue to continue forming a stiff peak.
Mix on high speed until the meringue reaches room temperature. Once the meringue reaches room temperature, slowly begin incorporating the butter. Next, slowly add the strawberry puree, orange juice and food coloring.
Place the first layer of cake on a revolving cake stand. I prefer to leave the bottom cake round in place so it's easy to transfer the finished cake to a display stand (but remember to remove the parchment paper!).
Spread approximately one cup of buttercream on top and spread it around evenly with an offset spatula. Layer thin strawberry slices on top of the buttercream. Top the strawberries with a bit more buttercream.
Repeat with the second layer (remove the cake round this time).
Place the 3rd layer on top. Frost with a thin layer of buttercream. Use an offset spatula to apply a thin layer of frosting to the sides, taking care to make sure the top and sides are even. Chill in the refrigerator for at least 30 minutes to set this first layer of buttercream.
Cover the entire cake with a final layer of frosting. For decoration, I used some fresh cream whipped with sugar and vanilla, topped with strawberries.
I strongly recommend weighing your flour, sugar and cornstarch on a kitchen scale, but if that's not an option, refer to this chart for cup measurements.
Adapted from Sweetapolita (the original cake has been removed so I'm linking to the homepage).