Add egg and sugar whisk until it becomes creamy if u do not have a whisking tool use a spoon and turn

Add the vegetable oil or melted butter, milk and whisk until well mixed

Add flour and baking powder and whisk until it is well mixed

Divide the recipe into two, then add two tspn of cocoa powder into second mixing bowl

Now that you have a plain and chocolate recipe grease your pan and pour in the recipe alternatively

Like first two spoon of plain recipe, then two spoon of chocolate recipe, and continue to pour the recipe ontop of each other then bake your cake for 40 minutes.