2In a large bowl, combine 2 cups (240g) of all-purpose flour, 1 teaspoon of salt, and 2 teaspoons of baking powder. Whisk until combined.
3In a separate large bowl, cream together ½ cup (113g) of room temperature butter and ¾ cup (150g) of granulated sugar for about a minute on low speed.
4Add 2 large room temperature eggs and mix for a few seconds on medium speed.
5Add the lemon zest (from one whole lemon).
6Mix on medium speed for about 2 minutes until light and fluffy.
7Add 2 teaspoons of vanilla extract and mix.
8Add the dry ingredients in three additions, alternating with the milk, mixing on low speed in between.
9Gently fold in the blueberries.
10Prepare the streusel topping by mixing together ½ cup flour, ½ cup sugar, ¼ cup butter, and a pinch of salt.
11Fill muffin cups about ¾ full. Top some muffins with streusel topping and others with a sprinkle of sugar.
12Place a ramekin filled halfway with water in the oven to prevent muffins from drying out.
13Bake at 400°F for 20 minutes, until puffed and golden.