For the Blueberry Chocolate Cake

1. Heat your oven to 350 degrees. Grease the sides and bottom of a 9×13 inch rectangular cake pan with butter.
2. Cut parchment to fit the bottom of the pan. Press the parchment down into the bottom of the pan. Grease the parchment with butter again. Set aside.
3. In a non stick saucepan on medium low heat, melt the 1 cup of unsalted butter.
4. Once melted, add the 8 ounces of bittersweet chocolate and stir until chocolate is smooth and melted. Allow to cool.
5. While the chocolate cools, place the 2 cups of flour, 1 cup of cocoa powder, 2 tsp of baking powder, 1 tsp of baking soda, and 1/2 tsp of salt in a medium sized bowl and whisk to combine.
6. In another larger bowl, mix together the 2 cups of packed brown sugar, 4 large eggs, and 2 tsp of vanilla. Stir well to combine.
7. Next, take the cooled chocolate and pour it into the bowl with the wet ingredients (the brown sugar and egg mixture).
8. Next, add some of the dry ingredients (the flour and cocoa mixture) to the bowl of wet ingredients. Stir well, and pour in a little of the 1 cup of buttermilk.
9. Then, add more of the flour mixture to the wet mixture, alternating between dry ingredients and the buttermilk, stirring between each addition. Be sure to start and end with the flour mixture.
10. Once that is finished, stir in the 2 cups of fresh blueberries a bit at a time, stirring gently so the batter does not become overworked.
11. Once the blueberries are incorporated, pour the cake batter into the prepared cake pan.
12. Place the cake in the oven on the center rack and bake for 30 minutes. At the 30 minute mark, start checking for doneness using a cake tester or tooth pick.
13. If there is batter stuck to the tester, keep baking in 3 to 5 minute intervals, checking for doneness until the tester or toothpick in the center comes out clean. In my oven, this took 45 minutes but each oven is different and yours could take less (or maybe a little more) time than my oven takes.
14. Allow the cake to cool before frosting (at least 2 hours). Now, for the buttercream!

For The Blueberry Buttercream

1. First, make the blueberry puree. In a small saucepan over medium low heat, add the 1 cup of blueberries, 1/4 cup of granulated sugar, and the pinch of nutmeg and cardamom.
2. Simmer for about 10 to 15 minutes until the berries are soft. Pour the mixture into a blender and puree until smooth.
3. In the bowl of a stand mixer with a paddle attachment, beat the 2 cups of unsalted butter until pale in color and creamy, about 3 to 5 minutes.
4. Add 1 cup of the powdered sugar and reduce the mixer speed a little.
5. Next, add about 4 tablespoons of the blueberry puree and the 1/8 tsp of salt.
6. Add 2 to 3 more cups of powdered sugar and 4 more tablespoons of blueberry puree.
7. Continue mixing and add a little heavy cream one tablespoon at a time, until the frosting is a smooth spreadable consistency, not thick or runny.
8. To frost the cake, spread the frosting evenly over the top of the cake (the frosting layer will be thick). Drizzle with the top of the frosting with the remaining blueberry puree and cover the top with extra fresh blueberries.