Heat the butter slightly to soften it, then beat it well with the powdered sugar. Gradually add the yolks to them.
Add the cocoa to 1/3 of the mixture. Alternate between the 2 mixtures, while pouring them in a buttered and floured form.
Bake in a moderate oven. Take the baked cake carefully out of the form and place it on a metal cooking grid.
Pour the mint syrup into a separate container and let it reduce by half. To it, add the chocolate. Pour this melted glaze over the cooled cake. Optionally, garnish with sliced almonds.