Preheat the oven to 350F.
Butter 2 (9-inch) round cake pans, or spray with baking spray.
Line the bottoms of the pans with parchment paper.
Add the all-purpose flour, baking powder, salt, and baking soda to a large bowl. Whisk to combine.
Add the butter to the bowl of a stand mixer with the paddle attachment (or a large bowl and electric hand mixer).
Beat the butter at medium speed, just until it begins to get fluffy.
Add the granulated sugar to the whipped butter.
Beat until light and fluffy, 4- 5 minutes.*Scrape down the sides and bottom of the bowl. Add the egg whites and vanilla to the creamed butter. Beat until at medium speed for about 1 minute or until well combined and fluffy.
Reduce the speed to low, then add half of the flour mixture. Mix just enough to combine.
Add the whole milk, mixing just enough to combine, then add the remainder of the dry ingredients and mix just enough to combine.
Add the strawberry reduction to the batter, mix just enough to combine.*Scrape the sides and bottom of the bowl as needed. Add a drop or two of pink food coloring to get the color of the batter to your preference. Divide the batter among the two cake pans.
Place the pans on the center rack of the preheated oven and bake for 30 minutes or until the cake is springy to the touch and starts to pull away from the sides of the pans.
Let the cakes cool in the pans on a wire rack for 20 minutes. Then, invert them from the pans onto the wire rack and let them cool completely.
Remove and discard the parchment paper.