Preheat oven to 180°C/350°F (160°C fan) and place the oven rack in the middle.

Line a cupcake tin with 12 cupcake liners.

In a bowl, sift together the dry ingredients: flour, caster sugar, baking soda, and salt. Whisk briefly to combine.

In a separate large heatproof bowl, add the butter and dark chocolate. Microwave for 45 seconds, stir, then microwave for another 30 seconds. Continue mixing until the chocolate is melted and smooth. If needed, microwave in 20-second bursts.

Add the cocoa powder to the melted butter and chocolate mixture, then mix well.

Pour in the milk and vegetable oil, then add the eggs, vanilla extract, and white vinegar. Whisk until everything is smooth.

Gradually add the flour mixture and whisk until it is lump-free.

Divide the cupcake mixture between the liners. An ice cream scoop works well for this and fill them just over 3/4 full.

Bake for 18 – 20 minutes, or until a skewer inserted into the middle comes out clean.

Remove from the oven and transfer the cupcakes to a cooling rack using a spoon or knife.

Once they are cool, spread your frosting on top and decorate with sprinkles if you like. You can also use Chocolate Buttercream Frosting for an extra treat!