1Make the jam by boiling together six cups of blackberries, half a cup of honey, one tablespoon of lemon juice, and one tablespoon of lavender until it's nice and thick.
2Make the vanilla cake batter by beating together one cup of coconut oil, half a cup of sour cream, three eggs, 1.5 cups of sugar, one tablespoon of vanilla, three cups of flour, half a teaspoon of baking soda, 1.5 teaspoons of baking powder and salt.
3Pour the batter into a baking dish lined with parchment paper.
4Dollop the jam into the batter and swirl it lightly with a knife.
5Bake the cake.
6Make the frosting by beating together two sticks of salted butter, 1.5 cups of powdered sugar, six ounces of melted white chocolate, and one teaspoon of vanilla.
7Spread the frosting over the cake.
8Add a little bit more jam and swirl it into the frosting.