Preheat the oven to 165°C and line muffin trays with papers.
Combine the flour, cocoa, baking powder and salt together in a bowl and set aside.
Then cream the butter, vanilla and brown sugar until pale and fluffy.
Add the eggs, one at a time, beating until well incorporated. Remember to scrape down the sides of the bowl as needed.
Add the flour and cocoa powder mixture in three batches, alternating it with two additions of buttermilk (or yogurt) and milk. Beat until well combined.
Put the batter into the lined muffin tray cups, filling each to about half.
Bake for about 15 to 20 minutes (25 minutes if you make bigger cupcakes).
When cooked, let them cool down in the tray for 10 minutes, then put them on a wire rack to cool down completely.
Snow Icing
Whip the cream and sugar until soft peaks are formed.
Keep it in the fridge until ready to pipe.
Snowflake Decorations
You can use a template to pipe your Royal Icing snowflakes, or do them by hand (which is what I did).
Mix some blue food colouring to the Royal Icing.
Pipe out the snowflakes into a piece of baking paper.
Add a sugar pearl in the centre of each piped snowflake and let them dry completely. (You can make these a couple of days in advance)
To Assemble the cupcakes
Put the whipped cream in a piping bag and decorate the chocolate cupcakes with it.