Preheat oven to 350 degrees. Line your muffin pan with paper muffin liners.
Start by making your streusel topping. In a small bowl combine the flour, sugar and butter. To make the crumbles start by pinching your fingers together in the mixer until crumbles form. Set aside until your muffin batter is ready.
In a small bowl, whisk together flour, baking powder and salt and set aside. In a large bowl, beat butter and sugar until light and fluffy.
Add eggs, vanilla and milk. Add flour mixture and stir until just combined. Carefully stir in blueberries.
Divide batter evenly into 12 muffin cups. Sprinkle muffins with streusel topping.
Bake for 20 to 25 min, until a tester inserted into the center comes out clean.
When muffins are done, cool for a few minutes in the muffin pan before removing to cool on a wire rack.