Preheat oven to 375 degrees F and grease a cookie sheet.
Whisk together the flour (except the 1 tablespoon), sugar, baking powder, lemon zest, and salt.
Using a pastry/dough blender, cut in the butter until butter is incorporated except for a few spots of butter. You could also use a fork to cut the butter in.
Add the lemon juice, yogurt, milk and egg in a separate bowl, mixing. Add this mixture to the dough and mix until it just comes together. The dough should be thick.
In a separate bowl, toss the blueberries with the 1 tablespoon of flour to coat. Add the Stir in the blueberries carefully into the dough.
Place dough unto cookie sheet and form into a circle, evening out the dough until it is about 1 inch thick. Cut the dough equally into 8 pieces (I usually cut in half, then into four, then six, then eight).
Bake for 17 minutes. Transfer to a wire rack to cool and prepare glaze.
Glaze
Mix all the ingredients together until smooth (run through a food processor if necessary). If too runny, add 1 tablespoon at a time of powdered sugar. If too thick, add 1 teaspoon at a time of milk.