Preheat oven to 350 degrees F.
For the cake - Add the flour, sugar, baking soda, 1/2 cup cocoa, and salt to a medium bowl and mix until well combined.
Add the vegetable oil and buttermilk blend in with an electric mixer.
Beat in eggs one at a time.
Slowly add the boiling water as you keep mixing with the electric mixer.
For the cream cheese filling - Add the cream cheese to a medium bowl and mix with an electric mix until fluffy. Add the sugar and beat in.
Add the egg and beat in.
Fill muffin tins that are lined with cupcake papers to 1/2 full. Add about 1/2 tablespoon of cream cheese filling in the middle of the batter.
Place the cupcakes in the oven and bake for 20 to 22 minutes or until when touching the top of the cupcakes springs back.
Remove from the oven and cool completely on a cooling rack.
Frosting- Add powdered sugar, butter, vanilla, and sour cream to a medium bowl. Beat the powdered sugar, sour cream, butter, and vanilla until they are well combined. Add the cocoa and beat until fluffy.
Frost each cupcake with a generous amount of frosting.