Strawberry Reduction

1. Prepare the strawberry reduction ideally a day before the cake. Combine strawberries, optional sugar, lemon zest, lemon juice, and a pinch of salt in a medium saucepan.
2. Cook on medium-high heat, stirring occasionally to prevent burning. Once the mixture starts bubbling, reduce the heat to medium-low.
3. Continue cooking until the mixture reduces by half and thickens to a consistency resembling tomato sauce. This should take approximately 20 minutes.
4. Once the reduction is ready, transfer it to another container and allow it to cool. Store as needed.

Strawberry Cake

1. Ensure that all ingredients, particularly butter, egg whites, and strawberry reduction, are at room temperature.
2. Preheat the oven to 350ºF (176ºC) and adjust the oven rack to the middle position.
3. Grease three 8″ cake pans using cake goop or a preferred pan release method.
4. In a medium bowl, whisk together the milk, strawberry reduction, strawberry emulsion, vanilla extract, lemon extract, lemon zest, lemon juice, and pink food coloring.
5. In a separate bowl, combine the flour, baking powder, baking soda, and salt.
6. Using a stand mixer with a paddle attachment, beat the room-temperature butter until smooth and shiny, then gradually add the sugar until the mixture is fluffy.
7. Incorporate the egg whites one at a time, ensuring the mixture remains cohesive.
8. On low speed, alternately add the dry ingredients and the milk mixture in thirds, mixing until just incorporated.
9. Divide the batter evenly among the prepared pans and smooth the tops.
10. Bake until a toothpick inserted in the center comes out clean or with a few crumbs, approximately 30-35 minutes.
11. Allow the cakes to cool in the pans on a wire rack for 10 minutes before transferring them out to cool completely.

Buttercream Frosting

1. Combine the egg whites and powdered sugar in a stand mixer bowl. Whip on low, then high for 5 minutes.
2. Gradually add softened butter, continuing to whip until the mixture is white, light, and shiny.
3. Incorporate the strawberry reduction, vanilla extract, and salt, continuing to whip until well combined.
4. Optional: Switch to a paddle attachment and mix on low for 15-20 minutes to smooth out the buttercream and remove air bubbles.

Cake Assembly

1. Trim the top of each cake layer if necessary to create a flat surface.
2. Place the first cake layer on a plate or board and apply a thin layer of cooled reduction, followed by a layer of strawberry buttercream.
3. Repeat with the remaining layers and frost the outside of the cake with the leftover buttercream.
4. Optionally, decorate with fresh strawberries.