Preheat airfryer at 200xb0C.
Remove 1 tbsp flour from the 1/2 cup flour and add 1 tbsp of cocoa powder or Nesquick. This is to make sure that the total dry component is 1/2 cup. Add baking powder and salt, in case you are using plain flour and not self raising flour.
Add baking soda, sugar and combine with a fork.
In a measuring jug or small bowl, whisk together milk, yogurt, oil and vanilla extract until combined.
Make a well in the dry ingredients and add the wet ingredients. Add the vinegar.
Stir to combine. Do not over mix, a few lumps of flour are ok at this stage. Mix in the chocolate chips.
Spoon the mix into 6 silicone cupcake / muffin moulds
Place 4 at a time in the wire basket of the preheated airfryer.
Set timer at 8 minutes, after which you can insert a skewer / tester to see if it comes out clean. You can keep the second batch to bake at this point.
Remove and cool for 5 minutes. Remove from moulds and serve or store in airtight container in refrigerator.
You can store this for 4-5 days in the refrigerator in an airtight box.