I use frozen berries as this keeps the blueberries whole whilst baking (and not just mushy). It makes 12 large muffins so if you wish to use cupcake cases this would make a lot more.
These are fantastic! I used fat-free greek yoghurt and didn't feel the need to sprinkle the sugar/cinnamon at the end. Perfectly moist and low fat -- winner :o) - 06 Jul 2017