Prepare for Baking:
Preheat your oven to 350°F (175°C). Grease and line two 9-inch round cake pans with parchment paper.
Mix the Dry Ingredients:
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
Cream Butter and Sugar:
In a large mixing bowl, beat the butter and sugar together until light and fluffy, about 2–3 minutes.
Add Wet Ingredients:
Beat in the eggs, one at a time, followed by the lemon zest, lavender, and vanilla extract.
Incorporate the Dry Ingredients:
Gradually add the dry ingredients to the butter mixture, alternating with the milk and lemon juice. Begin and end with the dry ingredients, mixing until just combined.
Bake the Cakes:
Divide the batter evenly between the prepared cake pans and smooth the tops with a spatula.
Bake for 25–30 minutes, or until a toothpick inserted in the center comes out clean.
Let the cakes cool in the pans for 10 minutes, then transfer them to a wire rack to cool completely.
Prepare the Lemon Glaze:
In a bowl, whisk together powdered sugar, lemon juice, and milk until smooth. Adjust the consistency with more lemon juice or powdered sugar as needed.
Assemble and Glaze:
Once the cakes are completely cool, place one layer on a serving plate. Spread a thin layer of glaze on top.
Place the second layer on top and pour the remaining glaze over the cake, letting it drip down the sides.
Garnish with a sprinkle of dried lavender buds if desired.