Preheat oven at 180 degrees Celsius and line a 7 inch cake pan.
In a bowl add yogurt and baking soda and let it sit for 5 minutes.
Add sugar, oil, vanilla, milk and whisk it till all the sugar is dissolved.
Fold the dry ingredients in without over mixing the batter.
Divide the batter equally into 2 bowls. Make a slurry of cocoa powder and hot water and add it into the first bowl . Mix it well and your chocolate batter is also ready .
Transfer the batter in the prepared tin with a scoop or piping bag , alternatively starting with chocolate and vanilla over it till all the batter is used .
Bake for 40-45 mins or till a skewer inserted in centre comes out clean .
Once the cake has cooled completely, demould and serve .
Recipe by Bake with Shivesh at https://bakewithshivesh.com/zebra-cake/