1. Preheat oven to 400 degrees Fahrenheit. Grease 12 mufﬁn pan cups.
2. In small bowl, beat egg, milk, lemon zest, and vanilla extract until blended. Stir egg mixture into ﬂour mixture just until ﬂour is moistened. (Batter will be lumpy.) Fold blueberries into batter. If frozen blueberries are used, do not thaw before adding to batter.
3. Spoon batter into mufﬁn pan cups. Bake 20 to 25 minutes until golden and toothpick inserted into center comes out clean. Immediately remove from pan. Serve warm.
4. In a large bowl, mix ﬂour, sugar, baking powder and salt. With pastry blender or two knives used scissor-fashion, cut in butter until mixture resembles ﬁne crumbs.