To make puree, place a handful of strawberries in a blender and puree on high speed until smooth. Divide the mixture into 1/4 cup for the cake and 1/2 cup for the buttercream.
Preheat the oven to 350 degrees F. Prepare 3 8-inch cake pans. My method is to spray a small amount of baking spray in the bottom of each pan, then line each with parchment rounds. You can use butter and flour instead, but don't grease the sides with either method. Set aside.
In a medium bowl, combine the puree, half-and-half, vanilla, and orange juice. In a separate large bowl, whisk together the flour, cornstarch, baking powder, salt and zest. Break up any clumps of zest by hand.
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 wet and dry ingredients, beginning and ending with the dry. Scrape down the bowl one more time.
Divide the mixture in half. In one bowl, add a few drops of red food coloring and mix well (gel food coloring works best). Divide the 2 mixtures between the 3 cake pans, adding large dollops of each color without mixing. Use a teaspoon to draw swirls in the batter (a figure 8 motion works well). Be careful not to over-swirl or the result will be a pale pink cake. Give the pans a gentle shake to help disperse the batter evenly.
Bake for 22-25 minutes, or until a toothpick comes out clean.
Allow the cakes to cool for several minutes in the pan. Carefully invert them onto a cooling rack or onto cardboard cake rounds lined with parchment. Allow the cakes to cool completely. Once cool, they can be wrapped in plastic and stored at room temperature for two days, the refrigerator for five days, or the freezer for several months.
Prepare the strawberry buttercream:
Add sugar, water and corn syrup (if using) to a medium saucepan; 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. Remove the parchment paper.
Spread approximately one cup of buttercream on the cake and spread it around evenly with an offset spatula. Add more buttercream as needed to reached the desired thickness.
Repeat with the second layer.
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 in a decorative pattern.
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.