Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt.
Grate or cube the butter, add it to the dry ingredients, and toss gently to coat the butter in flour.
In a separate bowl, whisk together the cooled lavender milk, egg, vanilla extract, lemon juice, and lemon zest.
Pour the wet ingredients into the dry ingredients and mix until a shaggy dough forms. Be careful not to overmix.
Turn the dough onto a lightly floured surface and gently pat it into a rectangle. Fold the dough in half, then rotate it and fold again. Repeat this process 2–3 times to create flaky layers.
Shape the dough into a 1-inch thick round disc, wrap it in plastic wrap, and chill in the refrigerator for 20 minutes (or 10 minutes in the freezer).
Remove the dough from the plastic wrap and cut the dough into 8 wedges. Transfer the scones to the prepared baking sheet.