Start with the dry mix. In a bowl, whisk together flour, cornstarch, baking powder, and salt until evenly combined. Set aside. In a larger bowl, beat the softened butter with sugar until it turns pale, fluffy, and smooth.

Add egg whites little by little, mixing well each time so the mixture stays creamy. Pour in the oil and vanilla, then mix again until fully blended.

Now add the dry ingredients and milk in small batches, alternating between them. Stir gently just until the batter is smooth and lump-free.

Pour the batter evenly into the two cake pans. Bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean. Let the cakes cool completely on a rack.

For the frosting, cook the strawberries over low heat until they soften and become thick like a jam. Cool it completely. Beat butter until creamy, then mix in the strawberry mixture, powdered sugar, vanilla, and salt. Whip until light and fluffy. Add cream if the frosting needs to be softer.

To finish, place one cake layer on a plate, spread frosting evenly, add the second layer, and cover the entire cake with the remaining frosting. Chill before slicing for the best texture and clean layers.