Cream together the butter and 60ml/4 tablespoons of the sugar till light and fluffy. Stir in the flour and lavender and work it in, kneading with your hands till it comes together into a soft ball of dough. Cover with cling film and chill in the fridge for 15 minutes. Roll out on a lightly floured surface. Stamp out the cookies with a heart shaped cutter (alternatively a fluted-edged round cutter). Makes about 18 with a 5cm/2inch cutter. Put carefully onto a lightly greased baking tray and sprinkle the remaining sugar onto the top of each shape. Bake at 200C/400F for about 10 minutes till golden. Leave the cookies on the tray for 5 minutes, before putting on to a cooling rack.