Preheat the oven to 160˚C. Line a 20cm cake or sandwich tin with parchment paper.
In a bowl, beat the butter and sugar together until smooth. Add the vanilla extract and flour and ground almond. combine to a smooth crumb.
Transfer the dough in the tin and gently push the dough until levelled.
Brush with an egg wash if desired and sprinkle with the flaked almond and a sprinkle of caster sugar.
Bake in the oven for 25-30 minutes, or until pale golden-brown. Remove from the oven and set aside to cool on a wire rack. Store in a tight container and enjoy with in a week for best freshness.