Preheat the oven to 350°F (180°C) and line a baking sheet with parchment paper.
Zest the lemon into a small bowl and set aside.
Juice the lemon and set aside 1 teaspoon for the glaze. Combine the rest with ½ cup (120 ml) of almond milk and set aside for 5-10 minutes while you make the rest of the dough. (The almond milk will curdle, that’s okay! This creates a dairy-free substitute for buttermilk.)
In a large bowl, combine the flour, sugar, baking powder, salt, poppy seeds, and lavender. Whisk well.
Add the coconut oil and cut it into the flour mixture with a pastry cutter, a fork, or your fingers until the flour mixture is crumbly and there are no large chunks left.
Add the lemon zest, curdled almond milk, and egg. Fold the ingredients until the dough forms.
Transfer the dough to a lightly floured surface. Sprinkle with just enough flour to keep the dough from sticking as you form it into a disc about 1½-2 inches (4-5 cm) thick.
Cut the dough into 8 triangular scones. Transfer the scones to the prepared baking sheet, spacing evenly.
Bake for 20-25 minutes, or until golden brown. Let cool.
Make the glaze: In a small bowl, combine powdered sugar, remaining 1-2 teaspoons of almond milk, and the reserved teaspoon of lemon juice. Whisk until smooth.
Drizzle the glaze over the cooled scones and let it harden, 5-10 minutes.