Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Beat in the eggs, one at a time, followed by the vanilla extract, lemon zest, and lemon juice.

Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined.

Gently fold in the fresh blueberries, being careful not to overmix.

Divide the batter evenly among the prepared cake pans and smooth the tops with a spatula.

Bake in the preheated oven for 20-25 minutes, or until a toothpick inserted into the center of the cakes comes out clean.

Allow the cakes to cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.

In a large mixing bowl, beat the softened butter until creamy.

Gradually add the powdered sugar, one cup at a time, beating well after each addition.

Add the lemon juice, lemon zest, and vanilla extract, and beat until smooth.

If the frosting is too thick, gradually add heavy cream, one tablespoon at a time, until the desired consistency is reached.

Once the cakes are completely cooled, place one layer on a serving plate or cake stand.

Spread a layer of frosting over the top of the cake layer.

Place another cake layer on top and repeat the process until all layers are stacked.

Use the remaining frosting to cover the top and sides of the cake, creating a rustic naked appearance.

Decorate the top of the cake with fresh blueberries, lemon slices, and mint leaves for a beautiful finishing touch.