Preheat your oven to 350°F (175°C). Grease and line three 8-inch cake pans with parchment paper.

In a medium bowl, combine the all-purpose flour, baking powder, and salt – whisking them together to create a uniform mixture.

In a larger mixing bowl, beat the softened unsalted butter and granulated sugar together until you achieve a light and airy consistency.

Next, add the eggs one at a time, ensuring each is well incorporated before adding the next.

Stir in the vanilla extract and finely ground lavender.

Now, starting and ending with the dry mixture, alternately mix in the flour combination and milk until combined.

Gently fold in the sour cream to introduce extra moisture.

Divide the batter evenly among the three pans, smoothing the tops.

Bake for 22-25 minutes or until a toothpick inserted into the center emerges clean.

Allow cakes to cool completely before assembly.

In a mixing bowl, combine softened mascarpone cheese, heavy whipping cream, and powdered sugar.

Beat these together until fluffy with a hand mixer or stand mixer.

Gently fold in the strained blackberry puree and remaining vanilla extract, mixing until smooth and well-blended.

Refrigerate this luscious filling for at least 30 minutes before using—it will become even creamier as it chills.

Over medium heat in a saucepan, combine fresh blackberries, powdered sugar, and lemon juice.

Mash the blackberries while they cook, allowing them to break down into a vibrant mixture.

In a separate bowl, mix cornstarch with water until it reaches a slurry consistency.

Stir the slurry into the blackberry mixture and cook until the glaze thickens, about 3-5 minutes.

Strain through a fine-mesh sieve to remove any seeds, and let it cool completely.

Begin by placing one layer of cake on a serving plate.

Generously spread a portion of the blackberry mascarpone cream on top, smoothing it to the edges.

Place the second layer over this, repeating the process with cream.

Finally, top with the third cake layer.

To give the cake a semi-naked look, frost the outside with a thin layer of the mascarpone cream.

Pour the blackberry glaze over the top, allowing it to cascade down the sides.

To finish, adorn the cake with fresh blackberries and lavender blossoms for a stunning presentation.

A light dusting of powdered sugar adds a sparkling touch.

Be sure to chill the assembled cake in the refrigerator for at least an hour before slicing.

Serve slices to your delighted guests, and watch them revel in the harmony of flavors this cake offers!