This lemon marble cake is a tangy and delicious dessert that is perfect for any occasion. To make this cake, you will need all-purpose flour, baking powder, salt, unsalted butter, granulated sugar, eggs, vanilla extract, milk, lemon zest, and cocoa powder. The cake batter is divided into two parts, and one part is mixed with cocoa powder to create the chocolate batter. The two batters are then swirled together with lemon zest to create the marble effect. This cake is moist, tender, and has a beautiful lemon and chocolate swirl pattern. It's perfect for anyone who loves lemon desserts.