Preheat oven to 350°F (180°C) and line a muffin tray
In a bowl, whisk eggs, oil, milk, Greek yogurt, and vanilla until smooth
In another bowl, combine flour, cocoa powder, sugar, baking soda, baking powder, and salt
Pour dry ingredients into wet ingredients and gently mix until just combined
Fold in chocolate
Fill the muffin liners almost to the top
Bake 18–22 minutes until set with a soft center
Cool slightly and enjoy
