Preheat the oven to 350°F (175°C). Grease and flour the cake pans.

In a mixing bowl, combine flour, sugar, baking powder, and salt.

Add softened butter, milk, eggs, lemon zest, and lemon juice. Beat on medium speed until smooth.

Divide the batter evenly between the prepared pans.

Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.

Allow cakes to cool in the pans for 10 minutes, then transfer to a cooling rack to cool completely.

In a mixing bowl, beat the softened butter until creamy.

Gradually add powdered sugar, lemon juice, lemon zest, and vanilla extract. Beat until fluffy.

Place one cake layer on a serving plate. Spread a layer of frosting on top.

Add the second cake layer and frost the top and sides of the cake.

Decorate with additional lemon zest if desired.