Preheat oven to 180 degrees. Grease and line an 8 inch baking pan.
Whisk the eggs with sugar until pale and fluffy. Add the oil, vanilla and red color and beat till incorporated.
Sift the flour, cocoa powder and salt into the mixture.
In another bowl, whisk together the buttermilk, vinegar and soda and allow it to froth. Immediately add into the mixing bowl and beat until just incorporated - do not overmix!
Pour immediately into pan and bake for 30-40 minutes or till skewer comes out clean.
Cool in pan for 5 minutes. Flip onto a cooling rack and cool completely.
For making the milk, whisk or blend together all the ingredients. Set in fridge till time of use.
When the cake is completely cooled, trim the sides and transfer into a bigger plate. Reserve the sides for decorating.
Poke holes using a fork. Pour around half the milk over the cake. Allow it to rest in the fridge for two hours.
To make the frosting, whip cream till soft. Add the rest of the ingredients and whip till done. Refrigerate till use.
Before serving, pipe out the frosting on top of the cake. Pour some more cream over it. Crumble the reserved cake and sprinkle on the top.
Serve cold with a drizzling of the remaining milk.
Notes
Do not allow the batter to rest after adding the soda mixture. Finish mixing and immediately get to baking. Keeping the batter will harden the cake.