Combine flour, sugar, baking powder, and salt in a mixing bowl. Cut butter into dry ingredients till crumbly. Stir in milk and lemon zest till just moistened.
Gently fold in blueberries and press dough into a ball.
Pat into a circle about 1″ thick on lightly floured counter. Cut into 8 wedges. Place 1-2 inches apart on a lightly greased cookie sheet. Brush tops with milk.
Bake at 400° for about 17 minutes or till golden brown. Cool slightly and drizzle with glaze.
For glaze, whisk together all ingredients in a small bowl until smooth.