Preheat oven to 400°F / 200°C.
Whisk flour, sugar, baking powder, salt, lemon zest and lavender together in a medium bowl.
Add cold butter to dry ingredients and use a pastry blender, fork, or your fingers to work the butter into the flour until it resembles coarse crumbs.
Remove 2 tbsp. of milk and set aside. We'll use this to brush the tops of the scones. Beat remaining milk and egg together, then add to dry ingredients and stir with spatula until just combined and no big pockets of flour remain.
Turn dough out onto lightly floured surface and press together - do not knead dough. Press out into a 1 inch thick round.
Dip a medium-sized cutter into flour, then press straight down into dough and pull straight up. Do not twist the cutter. Place scones on parchment-lined baking sheet. Repeat until all the dough is used up. Gather and lightly press dough together to cut the last few.
Brush tops with reserved milk, sprinkle each scone with 1 tsp. coarse sugar and bake for 14 - 16 minutes.
Place on cooling rack to cool slightly before serving.