Finely chop the chocolate, place in a bowl then set aside.
In a small saucepan, mix together the cream and both extracts. Heat over low heat until it starts to bubble.
Pour the cream over the chocolate then let it sit for 5 minutes before gently stirring it all together until smooth.
Place in the fridge for at least 2 hours to cool and firm up a little.
For the cupcakes
Preheat your oven to 180C / 350F (160C fan) and line your muffin tins with paper cases
In a bowl, sift together the flour, cocoa, baking soda, baking powder and salt. Mix well to combine.
In a separate bowl or the bowl of a stand mixer, beat together the melted butter and both sugars until smooth. Add the eggs one at a time, scraping down the sides of the bowl each time and beating well after each. Add the vanilla and beat to combine.
Add 1/3 of the flour mixture to the butter and sugar mixture. Stir through gently until just combined. Now add half of the buttermilk,
Mix gently again. Continue like this until all the flour and buttermilk is combined… just. It is important not to overmix or be too heavy handed otherwise your cupcakes will turn out dense and tough.
Fill the cupcake cases only to about half full. Bake in the oven for around 18-20 minutes, turning the pan around in the oven half way through to make sure they bake evenly. When a skewer inserted comes out with just a crumb or two, they are done.
Cool in the tin for 5 minutes before turning out onto a cooling rack. Let the cupcakes cool completely before proceeding
For the peppermint ermine buttercream
In a small saucepan whisk together the milk, flour, half the sugar and vanilla until smooth. Heat over low heat for 5-6 minutes until the sugar dissolves and the mixture thickens to a very thick paste. It's thick enough when you can see the lines of the whisk in the paste and the smell of uncooked flour has disappeared.
Pour into a bowl, cover with plastic wrap making sure the plastic wrap is touching the paste (this will stop the top from forming a skin), then place in the fridge to cool completely.
Once the milk paste is completely cool, beat together the butter and remaining sugar until really creamy (about 5 minutes). Make sure to regularly scrape down the sides of the bowl.
Add the milk / flour paste, salt and peppermint extract and beat on medium high for 5-7 minutes. If it looks like it separates at the start, don't worry, keep on beating and it will beat up into an almost whipped cream consistency.
Use a sharp knife or a cupcake corer, to cut a hole in the top of each cupcake.
Fill each hole with about 1/2 - 1 teaspoon of ganache (not too much as it's very rich). Top the ganache with a little bit of the cupcake offcuts to seal it in.
Transfer the buttercream to a piping bag and pipe in a big swirl on top of each cupcake.
I use a standard Australian 20ml tablespoon (4 teaspoons worldwide)
For best results you should always weigh ingredients like flour and sugar. Kitchen scales are relatively cheap but if you can’t weigh the ingredients, use the spoon and level method (don’t scoop).