Cream butter and sugar until pale and fluffy.

Add 1 or 2 egg yolks at a time and beat well.

Gently mix in milk followed by flour a little at a time.

Mix in vanilla extract.

In a separate bowl, add egg whites and beat until foamy.

Add half the sugar and beat. Then add the remaining half and beat till stiff peaks form.

Gently mix in one third of egg white mixture to batter. Slowly add in the remaining egg white mixture 2 more times.

Remove bowl from mixer and use a spatula to gently fold in egg white mixture until well incorporated.

Divide the batter into 3 equal portions and sieve cocoa powder into one.

Mix thoroughly with a spatula until cocoa is evenly distributed.

Scoop cocoa batter mixture into a piping bag. Leave a little in the bowl for the next mixture.

Add other 1/3 batter with instant coffee powder into the bowl and mix to get a lighter shade

Transfer to another piping bag.

Transfer the remaining ⅓ batter to a piping bag also.

Altogether there will be 3 piping bags of 3 shades of batter mixture.

Thoroughly grease a Heritage Bundt pan with butter.

Carefully pipe each shade of batter into every 3rd groove of the Heritage Bundt pan.

Knock bundt pan on a hard surface to remove trapped air and to smoothen the surface.

Bake in preheated oven at 170C for about 40 mins. Lower temp to 150 C for the last 20 mins. Watch cake closely for the last 20 mins to prevent over baking. As each oven is different, please adjust baking temperature and timing accordingly.

Cake is done once a skewer, inserted near the centre, comes out clean.

Cool pan on a wire rack for about 10 mins.

Clear the center of the cake with a skewer before overturning with a plate.

Let the pan cool down slightly before lifting it up.