Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan or line it with parchment paper.
In a mixing bowl, combine the flour, sugar, dried lavender, baking powder, baking soda, and salt. Whisk until well combined.
In another mixing bowl, cream the softened butter using a whisk or mixer until light and fluffy.
Add the eggs one at a time to the butter, mixing well after each addition. Then, mix in the buttermilk and vanilla extract until smooth.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Be careful not to overmix.
Gently fold in the fresh blueberries, ensuring they are evenly distributed throughout the batter.
Pour the batter into the prepared cake pan, smoothing the top with a spatula.
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Once done, remove the cake from the oven and let it cool in the pan for 10 minutes before transferring it to a cooling rack to cool completely.
Once cooled, dust the top with powdered sugar and garnish with additional blueberries if desired. Serve and enjoy!