Start by preheating the oven to 220℃, line a muffins/cupcake tray with paper cases or just use square sheets of baking paper and rustically line the tray.
In a large bowl add the eggs, milk, melted butter, vanilla and whisk until combined.
Add the flour, baking powder, baking soda, salt, castor sugar, blueberries and using a rubber spatula stir together until combined. Do not over mix.
Scoop 1/2 cup worth of batter into the lined muffin tray, alternating each mould, this helps them rise while baking. If you don’t have a large enough tray, bake the batter in batches.
Sprinkle the top with granulated sugar and cinnamon. Bake for 5 minutes at 220℃, turn the oven down to 180℃ and bake for 20 mins until a tooth pick inserted into the center comes out clean.
Remove from the tray and let them cool on a wire rack.