Preheat your oven to 425°F (220°C) and prepare muffin tins with liners.

In a large bowl, whisk together flour, sugar, cocoa powder, baking soda, and salt.

Make a well in the dry mixture and add the eggs, Greek yogurt, olive oil, milk, and vanilla. Whisk until smooth.

Gently fold the dry and wet ingredients together without overmixing. Fold in the chopped chocolate.

Using an ice cream scoop, fill each muffin liner evenly with the batter and top with reserved chocolate pieces.

Bake at 425°F for 5 minutes, then reduce temperature to 350°F and bake for 15-20 minutes.

Let muffins cool in the pan for 5 minutes before transferring to a wire rack.

Heat heavy cream for ganache, then pour over chopped chocolate and whisk until smooth. Chill before injecting into muffins.