Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans. Line the bottoms with parchment paper for easy removal.
In a large mixing bowl, combine the flour, sugar, baking powder, baking soda, and salt. Whisk together to mix well.
In a medium mixing bowl, cream together the softened butter and granulated sugar using an electric mixer until light and fluffy.
Add the eggs one at a time, beating well after each addition. Mix in the buttermilk, vanilla extract, and dried lavender.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
Gently fold in the fresh blueberries.
Divide the batter evenly between the two prepared cake pans.
Bake in the preheated oven for 30-40 minutes or until a toothpick inserted into the center comes out clean.
Let the cakes cool in the pans for about 10 minutes, then turn them out onto a cooling rack to cool completely.
Once cooled, frost with your favorite icing or serve plain for a simple treat.