Preheat oven to 375°F (190°C) and line a 12-cup muffin tin with paper liners
Melt 3 tablespoons butter in a microwave-safe bowl for the streusel topping
In a small bowl, combine 1/2 cup flour, 1/2 teaspoon cinnamon, 1/2 cup brown sugar, and melted butter for the texture topping
Chill the streusel in the refrigerator until ready to use
In a heavy skillet, melt 1/2 cup butter over medium heat until golden brown with a nutty aroma
Cool browned butter slightly and whisk in 1 cup sugar until smooth
Add eggs one at a time, blending well after each
Mix in milk, baking powder, salt, and 1 teaspoon vanilla
Fold in 2 cups flour just until combined
In a separate bowl, coat blueberries in 2 tablespoons of all-purpose flour to prevent sinking
Gently fold blueberries into batter using a spatula
Divide batter evenly into prepared muffin cups (about 2/3 full)
Top each with a heaping tablespoon of streusel topping
Bake for 23-28 minutes until golden brown and toothpick inserted comes out clean
Cool for 5 minutes, dust with powdered sugar if desired, then serve