Chocolate Ganache: Heat your cream in the microwave in 20 second intervals until hot to the touch (i did 1 min for mine). Add in the dark chocolate chips, leave for 3 minutes and then stir until it is well incorporated. Set aside in the fridge to cool.
Preheat oven to 180C/350F.
Batter: In a bowl, combine the flour, sugars, cocoa powder, baking powder, baking soda and salt. Add in the buttermilk, oil, eggs and vanilla and mix well until combined (do not overmix!). Add in the melted chocolate and fold gently into the batter. Lastly, add in the chocolate chips and mix until just combined.
Divide the batter evenly into a lined muffin tray, for 6 muffins. Top with extra chocolate chips and bake for 18-22 minutes, or until the toothpick comes out dry with small crumbs. Set aside to cool for 15 minutes, otherwise it will melt your ganache too much.
Meanwhile, stir your ganache and transfer into a piping bag. Now that your muffins have slightly cooled, make a hole in the middle of each muffin using a chopstick. Then pipe some ganache into each center. Enjoy!