In a food processor, mix the brown sugar and lavender buds until the buds are broken up and you see fine pieces in the sugar. The sugar will turn lighter in colour due to the air going into it.
In a large mixing bowl, mix the food processed brown sugar and lavender with butter. Mix until blended and no large butter lumps left.
Mix in egg and plain yogurt. Mix until blended.
Mix in baking powder, baking soda, salt, and the flour. Mix until blended, do not over mix. The batter will be tough.
In a medium bowl, coat blueberries in 1 Tbsp of flour to give it texture and this will prevent them from sinking to the bottom of the pan while baking. Gently fold the coated blueberries into the batter.
Bake in muffin pan lined with muffin cups or greased with butter, at 400 F for 5 minutes. Lower temperature to 350 F and bake for a remaining 15-20 minutes until toothpick test comes out clean in the centre of muffins. Let cool in the pan for 5 minutes before removing and cooling on a wire rack.