Preheat the oven to 180°C (160°C fan-forced). Line a 12-hole standard muffin pan with paper cases.
Using an electric stand mixer with a balloon whisk, beat butter and sugar together until light and fluffy. Add eggs, one at a time, beating until combined. Add flour, cocoa and baking powder, stirring gently until combined.
Add crème fraiche and milk, stirring until mixture is well combined. Add melted chocolate, stirring gently to combine.
Evenly divide mixture between paper cases and bake in preheated oven for 25 minutes or until a skewer comes out of the centre clean. Remove from oven and allow to cool in pan for 5 minutes, before turning onto a wire rack to cool completely.
Haigh’s Chocolate Ganache or Haigh’s Chocolate Buttercream
Place Haigh’s chocolate in a medium mixing bowl. Heat cream in a small saucepan over a medium heat, bring to just below boiling point. Pour over chocolate and gently stir to combine. Leave to stand for several minutes before stirring again.
Repeat process until chocolate has melted, making sure mixture is not over stirred.
Cover with plastic wrap and chill in refrigerator for 30 minutes to an hour, to firm up enough to spread or pipe.
For the buttercream:
Combine chocolate and cream together in a small mixing bowl over a saucepan of gently simmering water. Stir occasionally until chocolate has melted and mixture is smooth. Remove from heat and allow to cool completely.
Using a stand mixer with a balloon whisk attachment, beat butter and icing sugar together until light and creamy. Slowly add cooled chocolate mixture, beating until light and fluffy.