Preheat the oven to 400 ℉, and either line a rimmed baking sheet with parchment paper, a Silpat mat, or spray with non stick cooking spray.
In a medium sized mixing bowl, add the flour, brown sugar, granulated sugar, baking powder, baking soda, and salt.
2 cup flour, ¼ cup granulated sugar, ⅛ cup brown sugar, 1 teaspoon baking powder, 1 teaspoon baking soda, ½ teaspoon salt
Add in the softened, cubed butter and cut into the flour using your hands or a pastry cutter.PRO TIP: Freeze the butter, the grate it with a box grater. Then, add to the flour mixture and simply toss to coat with the dry ingredients. Makes cutting in butter a breeze! ½ cup butter
Mix in the poppy seeds so that they are evenly distributed. Make a well in the middle of the dry ingredients.
2 tablespoon poppy seeds
Add the egg, lemon juice, lemon zest, milk, and vanilla extract to the well in the dry ingredients.
¼ cup lemon juice, 1 teaspoon lemon zest, ¼ cup milk, 1 teaspoon vanilla extract
Mix ingredients together until a dough ball forms.
On a clean work surface, shape the ball of dough into a flat disc about 1" to 1½" thick, and about 9" to 10" wide. Cut into 6 equal wedges.
Transfer dough wedges to the prepared rimmed baking sheet. Brush with melted butter and sprinkle with sugar (optional). Bake for 10 to 12 minutes in preheated oven.
3 tablespoon melted butter, 3 tablespoon sugar
Remove and set on a cooling rack. Prepare the Lemon Glaze while cooling.