01 - Preheat oven to 350°F. Grease a 12-cup muffin tin or line with cupcake liners.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, and chopped lavender until well combined.
03 - In a large bowl, beat butter and sugar until light and fluffy, approximately 2-3 minutes.
04 - Beat in eggs one at a time, then mix in vanilla extract until fully incorporated.
05 - Combine milk and sour cream in a small bowl, stirring until smooth.
06 - Add flour mixture to the butter mixture in three additions, alternating with the milk mixture, beginning and ending with flour. Mix until just combined.
07 - Toss blueberries with 1 tablespoon flour, then gently fold into the batter until evenly distributed.
08 - Divide batter evenly among prepared muffin cups, filling each about 2/3 full. Bake for 22-25 minutes, or until a toothpick inserted in the center comes out clean.
09 - Cool in the pan for 5 minutes, then transfer to a wire rack to cool completely before glazing.
10 - Whisk powdered sugar and lemon juice until smooth. Drizzle over cooled cakes just before serving.