Preheat your oven to Gas Mark 4/180°C/350°F.
Line 8 muffin cups with paper cases and place an Oreo in the bottom of each one.
In a mixing bowl combine the flour, cocoa, sugar, rising agents and salt.
Add the egg, oil, milk and vanilla to the dry ingredients and whisk until there are no lumps left.
Add the hot water little by little, making sure the mixture does not become too runny.
Pour your mixture into the lined cups. Once half full you can add an extra broken up Oreo and cover it with a little extra batter. Fill them until they are about 3/4 full.
Place the muffin tray in the oven and bake for 20-25 minutes.
Once out of the oven, let them cool down slightly then place on a cooling rack until they are fully cooled down.
For the frosting, cut the butter into small cubes and place in a mixing bowl.
Add the icing sugar to the butter and beat until smooth with a whisk.
Add the Marshmallow Fluff and Vanilla, mix further until everything is fully combined. You may add food colouring if you wish to change the colour.
This frosting makes enough to spread on 8 cupcakes, if you wish to pipe it generously, you may need to double the quantities. Store this frosting in the fridge until needed.
*Sifting any powdered ingredients will make for less lumps and an overall smoother mixture.
*For the water, you may need to add more or less depending on your flour, as different flours absorb different amounts of liquid.
*The frosting is easier to mix if you use an electric whisk, but a handheld one is fine.
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