Rinse blackberries. In a medium sauce pan, combine the blackberries, 1/4 Cup of sugar and lemon juice. Cook covered on medium until the berries pop and they’re swimming in their juice.
Remove berries from stove and strain with a fine mesh strainer or cheesecloth. Pour juice back in sauce pan and set aside. The juice will be used for the Blackberry Buttercream Icing. The whole cooked blackberries will be used in the chocolate cake batter.
Preheat oven to 350 degrees and line a cupcake tray with cupcake liners.
In a large mixing bowl, whisk together the flour, remaining sugar, cocoa, espresso powder, baking soda and salt.
Add the oil, milk and vanilla and stir until smooth.
Fold in the whole cooked blackberries. Pour the mixture into each liner until it is 3/4 of the way full. Place pan in the oven and bake for 15-18 minutes.
Remove pan from the oven and poke one or two cupcakes with a toothpick to make sure they’re done. If it comes out clean, allow the cupcakes to remain out of the oven to cool. While the cupcakes are cooling, prepare the icing.
In another bowl, mix butter and blackberry juice together until smooth. Add powdered sugar, one cup at a time, mixing until smooth after each addition.
Add milk and vanilla and stir until blended. If the icing is too thick, add more milk 1 Tbsp at a time until desired consistency is reached. Pipe (or spread) icing onto cooled cupcakes and serve with a smile.