01 - Preheat your oven to 350°F and grease a 12-cup muffin tin or line with cupcake liners.
02 - Whisk together flour, baking powder, baking soda, salt, and chopped lavender in a medium bowl until well blended.
03 - Beat softened butter and granulated sugar in a large bowl until light and fluffy, approximately 2-3 minutes.
04 - Beat in eggs one at a time, fully incorporating each before adding the next. Mix in vanilla extract.
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 and sour cream mixture. Begin and end with the flour. Mix until just combined, being careful not to overmix.
07 - Toss blueberries with 1 tablespoon flour to prevent sinking, then gently fold into the batter.
08 - Divide batter evenly among prepared muffin cups, filling each approximately two-thirds full.
09 - Bake for 22-25 minutes until a toothpick inserted into the center comes out clean.
10 - Allow cakes to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
11 - Whisk powdered sugar and lemon juice until smooth. Drizzle over cooled cakes if desired.