01 - Preheat the oven to 350°F. Grease and flour an 8-inch round cake pan thoroughly.
02 - Whisk together flour, baking powder, and salt in a medium bowl. Set aside for later use.
03 - Beat softened butter and granulated sugar in a large bowl until light and fluffy, approximately 3-4 minutes.
04 - Add eggs one at a time, beating well after each addition. Mix in chopped lavender and vanilla extract until evenly distributed.
05 - Alternate adding flour mixture and milk to the butter mixture, beginning and ending with flour. Mix until just combined, being careful not to overmix.
06 - Transfer batter to the prepared pan. Use a spatula to spread evenly and smooth the top surface.
07 - Bake for 25-30 minutes until a toothpick inserted into the center emerges clean. The top should be lightly golden.
08 - While cake bakes, combine water, sugar, and lavender in a small saucepan. Simmer for 3 minutes, then strain and set aside to cool slightly.
09 - Let cake cool in pan for 10 minutes. If using syrup, poke small holes across the surface with a skewer and brush evenly with warm syrup. Allow to cool completely.
10 - Whisk powdered sugar, lemon juice, and chopped lavender in a small bowl until smooth and pourable.
11 - Drizzle the glaze over the completely cooled cake. Allow glaze to set for 15-20 minutes before slicing and serving.