Whisk flour, baking powder, baking soda, and salt together in a large bowl.
Whisk melted butter and sugar in a medium bowl.
Then add in the eggs, milk, and vanilla. Mix again.
Pour the wet into the dry ingredients and whisk just until everything comes together. Add fresh blueberries.
Bake for 5 minutes at 425F, then reduce the heat to 375 for another 15 minutes.
Divide the batter into 12 cups. Sprinkle with the streusel.
Divide the batter into 12 cups. Sprinkle the cinnamon streusel on top.