Blackberry Lavender Naked Cake with White Chocolate Buttercream

1. Preheat oven to 350° F. Grease 2 (8-inch) round cake pans. Line with parchment paper, then butter/spray with cooking spray.
2. In the bowl of a stand mixer (or use a hand-held mixer) beat together the canola oil, yogurt, eggs, sugar, vanilla, and buttermilk. Add the flour, baking soda, baking powder, and salt and mix until just combined. 
3. Pour the batter among the cake pans and bake 30-35 minutes, until the tops are just set and no longer wiggly in the center. Remove and let cool five minutes, then run a knife around the edges of the pan and turn the cakes out onto a cooling rack. Cover and let the cakes cool completely before assembling.
4. To make the jam. Add the blackberries, honey, lemon juice, and lavender to a medium-sized pot set over high heat. Bring the mixture to a boil, once boiling use a potato masher or fork to break down and mash the berries. Continue to cook for 5-8 minutes or until the jam has reduced and thickened by 1/3. Remove from the heat and let cool. Should thicken as it cools. 
5. To make the buttercream. Add the butter and powdered sugar to the bowl of a stand mixer. Beat the butter and powdered sugar together until the butter is light and fluffy. Add the melted white chocolate and beat until combined.
6. To assemble. Using a large serrated knife, carefully cut each cake in half horizontally. Place one cake layer on a serving plate. Spread 1/4 of the buttercream over the cake and layer with about 1/4 cup of jam. Repeat with the remaining 3 cake layers. Be careful not to overfill your layers or the cake will be hard to slice. Lightly frost the outside of the cake. Chill 30 minutes. Serve or store in the fridge for up to 3 days.