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 softened butter and granulated sugar with an electric mixer until light and fluffy, approximately 2-3 minutes.
04 - Beat in eggs one at a time, ensuring each is fully incorporated before adding the next. Mix in vanilla extract.
05 - In a small bowl, whisk together whole milk and sour cream until smooth.
06 - Add flour mixture to butter mixture in three additions, alternating with milk mixture, beginning and ending with flour. Mix until just combined, being careful not to overmix.
07 - Toss blueberries with 1 tablespoon flour in a small bowl to prevent sinking.
08 - Gently fold flour-coated blueberries into the batter using a spatula, taking care not to crush the berries.
09 - Divide batter evenly among prepared muffin cups, filling each about 2/3 full.
10 - Bake for 22-25 minutes, or until a toothpick inserted into the center of a cake comes out clean.
11 - Let cakes cool in the pan for 5 minutes, then carefully transfer to a wire rack to cool completely.
12 - If using, whisk powdered sugar and lemon juice in a small bowl until smooth and drizzle over cooled cakes.