Mix milk and lemon juice, leave it for 10 minutes.
Cream the butter and sugar for a minutes, add in eggs, mix well. Sift in flour, baking powder and cocoa powder, mix well.
Add in red food colouring and milk mixture, then add in baking soda+vinegar.
Evenly divide the batter into lined muffin tins. Pop in preheated oven at 170C, bake for 20 minutes or until fully cooked. Let it cool completely.
For Cream Cheese Frosting: Beat butter and cream cheese until smooth. Then sift in icing sugar and beat for 2 minutes until pale. Put the frosting into piping bag and decorate on cupcakes! Enjoy!