Heat the oven to 180°C (160° fan) gas 4. Place paper cases in a 12 hole muffin tin.
Melt the chocolate in a heatproof bowl over a pan of simmering (not boiling) water. Remove from the heat and set aside.
Whisk the egg yolks and sugar with an electric whisk until thick and pale. Stir in the melted chocolate and ground almonds until blended.
Whisk the egg whites to soft peaks and gradually fold into the mixture until incorporated.
Spoon into the paper cases. Bake for about 25 minutes, until firm on top; the tops may be slightly cracked. Cool in the tin for 5 minutes, then place on a wire rack to cool completely. 6 For the buttercream: beat the butter and peanut butter until smooth.
Sift in the icing sugar and salt and beat until just blended. Beat in the vanilla and cream until light and fluffy.
Spoon the buttercream on top of the cakes, swirling it with a knife. 9 Drizzle a little melted chocolate over the top and decorate with flaked almonds.