Preheat oven to 170°C. Line a 12 x 1/2 cup muffin tray with paper cases. Place 150g butter, melted and cooled, 2 eggs whisked, and the finely grated rind and juice of 1 orange in a bowl. Whisk to combine.
Stir in 2/3 cup caster sugar, 200g almond meal and 1 cup self-raising flour. Mix until well combined. Divide evenly among the paper cases.
Bake for 18-20 minutes or until golden and a skewer inserted into the centre comes out clean. Serve warm, dusted with icing sugar.