Preheat oven to 190 degrees C. Grease 12 muffin cups or line with patty cups.
Combine 2 cups flour, 2 teaspoons baking powder and 1/2 teaspoon salt in medium bowl. In a small bowl, sprinkle 1 to 2 tablespoons flour over blueberries and set aside. (This simple trick will keep you from having purple batter.)
In a large bowl, beat 125g butter with 3/4 cup sugar until light and fluffy. Beat in eggs, and stir in vanilla and lemon zest. Fold in dry ingredients alternately with milk. Fold in blueberries. Remember, fold gently, don't stir. Spoon batter into prepared cups.
Combine 2 tablespoons flour, 5 tablespoons sugar and 1/2 teaspoon cinnamon in a small bowl. Cut in 2 tablespoons butter with fork or pastry blender until mixture resembles course crumbs. Sprinkle over batter in muffin cups.
Bake in the preheated oven for 20 to 25 minutes, or until a toothpick inserted in centre of a muffin comes out clean. Cool in pans on wire rack. These muffins freeze really well, and re-heat in the microwave successfully. Hope you enjoy!!