Preheat oven to 375 °F/195°C. Line muffin pan with muffin liners.

Melt the chocolate chips in the microwave in 30 sec intervals, mixing in between until fully melted. Set aside to cool down.

Mix flour, baking powder, and salt in a large bowl.

In a separate bowl whisk together sugar and eggs. Add the cream cheese, yogurt, oil, and vanilla, keep whisking until the mixture is pale and fluffy.

Fold the wet ingredients into the dry ones, mix well.

Pour the melted chocolate on top of muffin dough. With a wooden spoon swirl melted chocolate into batter.

Spoon batter into prepared muffin tins, filling about ⅔ of each cup.

Place them in the oven and bake for 18-20 minutes or until the toothpick inserted in the center comes out clean.

Cool for 5 minutes in the pan then remove muffins and cool on a wire rack.