Preheat the oven to 375℉. Line a large baking sheet with parchment paper. Set aside.
Combine the buttermilk, lemon zest, and lemon juice to a large liquid measuring cup. Stir together and set aside.
Whisk together the flour, sugar, baking powder, salt, and poppy seeds in a large mixing bowl.
Grate the cold butter using the small side of a hand grater or box grater. Add it to the mixing bowl. Using your hands, combine until small pieces are formed.
Add the buttermilk mixture and, using a large spoons or a pastry cutter, stir just until the dough comes together, being careful not to over mix.
Turn the dough out onto a well-floured surface, dividing into two and then forming those into discs about 1-inch thick.
Place on prepared baking sheet. Slice each disc into 6 triangle-shaped pieces (like a pie).
Bake for 14-16 minutes or until lightly golden brown.
Transfer to a wire rack and cool.
To make the glaze, stir together the sugar 2 tablespoons of the lemon juice until smooth. If the mixture is too dry, add the remaining 1 tablespoon of fresh lemon juice. Mix together until it is a drizzlable consistency.
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