Preheat your oven to 350°F (180°C) and grease two 9-inch round cake pans.

In a mixing bowl, whisk together the all-purpose flour, cornstarch, baking powder, baking soda, and salt. Set aside.

In another mixing bowl, cream together the granulated sugar and room temperature butter until light and fluffy using an electric mixer.

Add the eggs one at a time, mixing well after each addition.

Mix in the sour cream, vegetable oil, lemon juice, lemon zest, and vanilla extract until smooth.

Gradually add the dry mixture to the wet mixture, mixing just until incorporated.

Divide the batter evenly between the prepared pans and smooth the tops.

Bake until golden brown and a toothpick inserted in the center comes out clean.

Let the cakes cool in the pans for a few minutes, then transfer to a cooling rack to cool completely.

Beat the softened butter until creamy, then gradually add the powdered sugar until smooth.

Add freeze-dried strawberry powder, vanilla extract, and enough milk to reach a spreadable consistency.

Place one cake layer on a serving platter, spread a layer of frosting on top, and then add the second layer.

Coat the entire cake with the remaining frosting and smooth to preference.

Decorate with fresh strawberries and lemon slices.