1) Pre-heat the oven to 350F/180C. Prepare 12×18 baking pan and line with parchment paper. Set aside.

2) Sift the flour, baking powder and salt in a separate bowl. Mix it well and set aside.

3) In a separate bowl combine egg yolks and 1 portion of sugar. Mix it well using a hand mixer till light yellow in color.

4) Then add oil and milk. Mix it well using hand mixer and gradually add the dry ingredients. Continue mixing till the batter is smooth and lump free. Set aside.

5) In a separate mixing bowl. Beat the egg whites on high speed using a clean paddle. Once frothy, add the cream of tartar and gradually add the 2nd portion of sugar. Continue beating till stiff peaks.

6) Fold-in the meringue and batter in three portions. Make sure not to over mix it or under mix it.

7) Transfer the 3/4 part of the cake mixture into the prepared baking pan. Mix the cocoa powder with the 1/4 portion of cake batter. Then pour the chocolate mixture around the cake mixture. Using a fork, swirl the chocolate batter around to create a marble effect. Bake for 55-60 minutes or till the stick test comes out clean.

8) Transfer to wire rack and remove the parchment paper to cool down completely.

9) For the frosting, using a hand mixer, mix the softened butter and icing sugar. Add the evaporated milk slowly, 1 tbsp. at a time. Set aside.

10) Once the cake has cooled down. Spread the frosting all over the cake. Then pour the chocolate syrup around the. Using an offset spatula, swirl the chocolate syrup around for the marble effect. Ready to serve. Enjoy!