This vegan marble cake recipe is perfect for those who follow a plant-based diet. It's made with simple ingredients like flour, sugar, baking powder, and plant-based milk. To make the cake, start by whisking together flour, sugar, baking powder, and salt. Then add plant-based milk, oil, and vanilla extract. Divide the batter in half and mix cocoa powder into one half. Pour the vanilla and chocolate batter into a greased loaf pan, alternating between the two. Use a knife to swirl the batter together to create a marble effect. Bake for 45-50 minutes at 350°F. Let the cake cool before slicing and serving.