Preheat oven to 180⁰C fan bake, and line 12 muffin tins with cupcake liners.
In a large bowl sift together the flour, salt, baking powder and cocoa. Combine with a whisk.
In a mixer (or with an electric hand mixer) cream the butter and Chelsea White Sugar. Add the vanilla extract and the egg and beat until light and fluffy.
In a separate dish mix together the buttermilk and the food colouring.
Alternately (in thirds) add the dry mixture and the buttermilk mixture to the creamed mixture. Scrape the sides of the bowl after each addition to ensure all ingredients are well combined. Mix well.
Remove mixing bowl from machine, and have a rubber spatula or wooden spoon ready to hand-mix with. Add the baking soda to the vinegar and quickly stir to dissolve baking soda. While still fizzing, add to the batter and mix through the liquid by hand.
Working quickly, spoon (or scoop with an ice cream scoop for even measures) the batter into the prepared cupcake liners (about ¾ full). Place in the oven, and bake for 18-20 minutes or until a skewer comes out clean when inserted into the centre of a cupcake.
Cool the cupcakes in the tin for 10 minutes before transferring to a wire rack to cool completely.
When cool, ice with cream cheese frosting.
Method for Cream Cheese Frosting:
In a mixer (or with an electric hand mixer) mix together the cream cheese, Chelsea Icing Sugar and vanilla extract. Whip the cream in a separate bowl. Fold the whipped cream into the cream cheese mixture by hand. The mixture should be thick and even in colour.
Spread on top of the cooled cupcakes, or pipe the frosting in swirls. Sprinkle crumbs of one of the cupcakes over the frosting for decoration (if you can bear to spare one!) or, use sprinkles of your choice.