Step 1

Preheat the oven to 350℉/180℃. Butter two 8 inch pans and dust with cocoa powder. Then line the bottoms with parchment paper. Set aside.

Step 2

In a small bowl, whisk the cocoa powder and the coffee (or hot water) together. Set it aside to cool.

Step 3

In a large bowl, whisk together the flour, the granulated sugar, the brown sugar, the salt, the baking powder, and the baking soda.

Step 4

In another bowl, whisk together the cooled cocoa/coffee mixture, the buttermilk, the eggs and the oil.

Step 5

Pour the wet ingredients into the flour mixture all at once, and whisk to combine. The batter will be thin (see the pictures in the post).

Step 6

Distribute the batter evenly among the pans and bake for about 40 minutes, or until a toothpick inserted in the middle comes out clean.

Step 7

When the cakes are done, remove them from the oven and let them cool in the pans for about half an hour. Then run a knife around the edges and flip the pans over to release the cakes.

Step 8

Remove the parchment paper and let the cakes cool completely on a wire rack before frosting.

Step 9

If you want to trim the tops of the cakes, put them in the refrigerator for at least half an hour first. The colder they are, the easier they'll be to trim.

Step 10

In a small saucepan, whisk together the sugar and cornstarch (this will help remove any lumps).

Step 11

Add the water and whisk together until it's smooth.

Step 12

Add the blueberries and lemon juice and cook over medium heat, stirring constantly.

Step 13

Bring to a boil and smash a few blueberries as they become softer. Cook the sauce until it thickens, about 2-3 minutes.

Step 14

Remove from the heat and let it cool to room temperature. You can also put it in the refrigerator to cool it down faster.

Step 15

Beat the butter on high speed until it's light and fluffy.

Step 16

Gradually add the powdered sugar in 3 batches. Beat on high for a few minutes until the mixture is smooth, scraping the sides of the bowl a few times.

Step 17

Add the cream cheese and vanilla and beat until it's just combined and smooth.

Step 18

Add ¼ cup of the blueberry sauce from above and beat until it's just combined. Don't overmix it or it could get runny. Reserve the remaining blueberry sauce to decorate the cake.

Step 19

This frosting is softish, but if you want it a bit thicker, you can add more powdered sugar.

Step 20

Place a cake layer on a cake stand or serving plate. Add half of the frosting on top and smooth it out. (If you want, you could add some blueberry sauce on top.)

Step 21

Place the second cake layer on top of the frosting. Add the remaining frosting on top and smooth it out evenly.

Step 22

Add the remaining blueberry sauce on top and swirl it into the frosting using the back of a spoon or an offset spatula.

Step 23

Add some more fresh blueberries on top.

Step 24

Enjoy!