Preheat oven to 400°F and line a muffin tin with muffin liners. Pick through blueberries to remove any stems or bruised berries.
In a large bowl, whisk together the flour, sugar, baking powder, and salt. Whisk the ingredients very well.
2 cups all purpose flour, 2 tsp baking powder, 1/2 tsp salt, 1 cup sugar
In a medium bowl whisk the eggs. Add the vanilla, melted butter, milk and lemon zest. Mix well. Pour the wet ingredients into the flour mixture and mix just until combined. Add the blueberries to the batter and gently mix. Fill each muffin liner with batter.
1.5 tsp vanilla, 1/2 cup milk, 1/2 cup melted butter, 2 eggs, 2 cups blueberries, zest of one lemon
Streusel Topping
Whisk together the flour, brown sugar, granulated sugar, salt, and cinnamon. Cut in the cold butter with a pastry cutter or fork until the mixture is crumbly. Sprinkle one tablespoon on top of each muffin.
1/3 cup flour, 3 tbsp brown sugar, 2 tbsp white sugar, 1/4 tsp cinnamon , 1/8 tsp salt, 3 tbsp cold butter
Bake
Bake for 20-22 minutes or until the tops of the muffins spring back when touched. Let the muffins cool for 2-3 minutes, then transfer to a wire rack.
Notes
Mixing: For soft, tender muffins use a light hand on the batter. Over-mixing will result in tough muffins!
Don't over-bake: For a soft, moist muffin, don't over bake! Take them out of the oven as soon as the muffins spring back when lightly pressed. Don't overbake.
Don't let the muffins cool in the pan, instead transfer them to a wire rack.