In a large bowl, sift together the flour, cocoa powder, baking powder, baking soda, and salt.
Whisk together the buttermilk, eggs oil and vanilla until smooth.
Gently fold the melted dark chocolate until fully combined.
Chill the batter for at least 20 minutes.
Preheat Oven: Preheat your oven to 200°C (400°F) and line a muffin tin with paper liners.
Scoop the batter evenly among the muffin liners, filling each about ¾ full.
Bake for 8 minutes on high and lower the heat to 150C and bake for 10 minutes or until a toothpick inserted into the center of a muffin comes out with a few moist crumbs.
Allow the muffins to cool in the tin for 5 minutes, then transfer them to a wire rack to cool completely.
In a small saucepan, heat the heavy cream over medium heat until it begins to simmer. Do not let it boil.
Place the finely chopped dark chocolate in a heatproof bowl. Pour the hot cream over the chocolate and let it sit for 2-3 minutes to melt the chocolate.
Gently stir the mixture until the chocolate is fully melted and the ganache is smooth. Let the ganache cool at room temperature until it thickens slightly, but is still pourable.
Once the muffins are cooled, use a small paring knife or a chopstick and poke the center of each muffin.
Pipe the ganache into the center of the muffins.
Let the ganache set before serving.
