Preheat oven to 425℉/220℃/Gas Mark 7.

Grease a muffin tin with either butter or non-stick spray.

In a large bowl, pour in the all-purpose flour, baking powder, salt, and cinnamon and whisk it together. Set aside.

In a separate medium bowl, add the brown sugar, granulated sugar, milk, yogurt, melted butter, and vanilla extract. With a hand mixer, beat the ingredients together. Next, add the first egg and beat that into the mixture. Then add the second egg and beat that in.

Pour the wet ingredients into the dry ingredients and mix together with a silicone spatula. Mix together until they are just incorporated. Do not overmix.

Lastly, add 3/4 of the chocolate chips.

Spoon the batter into the individual muffin tray. Put the leftover chocolate chips onto the tops of the muffins and sprinkle some granulated sugar onto the tops as well.

Bake for 5 minutes at the preheated temperature then with the muffins in the oven turn down the temperature to 350℉/175℃/Gas Mark 4 and bake for another 15 minutes. To check for doneness, insert a knife into a muffin and if it comes out clean then the muffins are done.

Let cool in the muffin tray for about 5 minutes than transfer to a wire rack and continue to let cool.