Preheat the oven to 185 degrees C
Line the 12 cups muffin pan with paper liners or just spray it with oil.
Add white vinegar to the milk. Keep it aside for 10 minutes.
Now take all purpose flour, sugar, cocoa powder, baking powder and salt in a bowl. Whisk it well.
Make a well in center of the dry flour mixture. Add prepared milk mixture, oil.
Gently fold in the dark chocolate chips.
Combine everything together. Do not over mix it.
Divide the batter in 12 muffin cups. Top with sprinkles.
Bake in preheated oven for 12 minutes or till the toothpick inserted in center of the muffins comes out clean. Then remove it on wire rack.
After 5 minutes remove the muffins from the pan and let it cool completely on wire rack.