Using a pestle and mortar, grind the chili flakes to a powder. Chop the dark and milk chocolate into small pieces and set aside.

In a small saucepan, bring the heavy cream to a boil and remove from heat. Add in the ground chili flakes and chopped chocolate and stir until smooth.

Let the ganache cool for about 2 hours in the fridge, until it has set but still can be stirred.

Add the butter to the ganache, and using a hand mixer, beat until smooth. Line a baking sheet with parchment paper.

Using a piping bag fitted with a Wilton 1A tip, pipe the chocolate ganache in circles onto the parchment paper. Let the truffles chill for 30 minutes in a cool place, then flatten the tips with your finger.

When the truffles have fully set, chop the chocolate into small pieces and melt over a double boiler.

Add some of the melted chocolate onto your hands and coat the truffles by rolling them on the inside of your palms. Immediately roll the truffles in cocoa powder and place onto a baking sheet and let them cool completely.

Store in the fridge and serve chilled.