1. Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
2. In a medium bowl, whisk together flour, baking powder, baking soda, and salt.
3. In a large bowl, cream the butter and sugar until light and fluffy. Beat in the vanilla extract, lemon extract, and lemon zest.
4. Add egg whites gradually, beating well after each addition.
5. Mix in the strawberry emulsion or extract, lemon juice, and strawberry reduction.
6. Alternately add the flour mixture and milk to the butter mixture, beginning and ending with the flour mixture. Add pink food color and mix until just combined.
7. Divide the batter evenly between the prepared pans. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
8. Let the cakes cool in the pans for 10 minutes, then transfer to wire racks to cool completely.

For the Strawberry Reduction

1. In a medium saucepan, combine strawberries, lemon zest, lemon juice, salt, and sugar (if using).
2. Cook over medium heat, stirring occasionally, until the strawberries break down and the mixture reduces by half, about 20-30 minutes.
3. Let cool to room temperature.

For the Easy Strawberry Buttercream Frosting

1. In a large bowl, beat egg whites until soft peaks form.
2. Gradually add powdered sugar and continue beating until stiff peaks form.
3. Add the butter a little at a time, beating well after each addition.
4. Mix in the vanilla extract and strawberry reduction until smooth and well combined.
5. Frost the cooled cake layers and assemble.