Mix the butter and sugar well with the whisk of the hand mixer; then work in the egg.
Mix flour with baking powder and add with the lavender leaves and flowers to the butter-sugar mixture and knead thoroughly with the dough hook of the hand mixer. Work through the dough well again by hand; if it sticks, add some flour and let it rest in the refrigerator for ½ hour.
Now roll out the dough and cut out biscuits with any shape you want. Place on a greased baking sheet and bake in a preheated oven at 220 ° C (fan oven 200 ° C) for about 10 minutes until the biscuits are golden yellow.