Preheat your oven to 375°F (195°C) and line a muffin pan with paper liners.

Melt the dark chocolate in a microwave-safe bowl in 30-second intervals until fully melted.

In a large mixing bowl, combine the flour, baking powder, and salt.

In a separate bowl, whisk together the sugar and eggs until pale and fluffy, then add cream cheese, Greek yogurt, vegetable oil, and vanilla extract.

Gently fold the wet mixture into your dry ingredients until just combined.

Pour the cooled melted chocolate over the batter and gently swirl it in.

Divide the batter among the muffin tins, filling each about ⅔ full.

Bake for 18-20 minutes or until a toothpick inserted in the center comes out clean.

Let the muffins cool in the pan for about 5 minutes, then transfer to a wire rack to cool completely.