1.Preheat oven to 180°C/350°F. Line eight holes of 12 hole (⅓ cup/80ml) muffin pan with paper cases.
2.Beat butter, extract, sugar, eggs, sifted flour and milk in small bowl with electric mixer on low speed until ingredients are combined. Increase speed to medium; beat until mixture has changed to a paler colour. Drop ¼ cups of mixture into paper cases.
3.Bake about 20 minutes. Stand cakes in pan 5 minutes before turning, top-side up, onto wire rack to cool.
4.To make butter cream, beat butter in small bowl with electric mixer until as white as possible; beat in sifted icing sugar and milk, in two batches.
5.Tint butter cream white with food colouring. Spread cold cakes with a thick layer of butter cream. Gently push halved mint leaves, smooth-side up and slightly overlapping, into butter cream in the shape of a wreath. Decorate leaves with cachous.