• Pre-heat the oven to 180C / 360F. Line a muffin tray with cupcake cases.
• Add sugar to the Thermomix bowl. Mill for 10 seconds / speed 9.
• Add butter and vanilla extract to the bowl. Cream together for 20 seconds / speed 4.
• Add the eggs, milk, flour, baking powder and cocoa powder. Mix for 20 seconds / speed 5.
• Use an ice cream scoop to divide the mixture into the prepared muffin tin.
• Bake in the oven for 20 minutes, or until a skewer comes away clean when inserted into the middle of a cupcake.
• Allow to cool for a couple of minutes before transferring to a cooling rack to completely cool before icing.

For the Buttercream Icing

• Add icing sugar to Thermomix bowl. Mill for 10 seconds / speed 9. Set aside.
• Add butter to the Thermomix bowl. Mix to soften for 10 seconds / speed 5.
• Add milk, vanilla extract, icing sugar and food coloring (if using). Mix for 30 seconds / speed 5.
• Transfer to a piping bag for icing cupcakes.