Preheat oven to 375F
In a large mixing bowl, beat together melted butter, granulated sugar, brown or coconut sugar, eggs, vanilla, and milk until smooth
Mix in all purpose flour, baking powder, salt, and cinnamon until just combined, being careful not to over mix
Toss blueberries in flour and gently fold them into the batter
Transfer batter to a lined muffin tin
Mix together streusel topping ingredients: brown or coconut sugar, all purpose flour, cinnamon, softened butter, and salt
Crumble streusel on top of muffins
Transfer to oven on middle rack and bake for 23-25 minutes
Let muffins rest for about 15 minutes before serving
Mix together cream cheese, powdered sugar, and milk to make icing
Top muffins with cream cheese icing
