Preheat the oven to 350°. Lightly grease 2 baking sheets or use parchment paper or silicone baking sheets. Set aside.
In a small bowl, using a fork or your fingertips, rub 1 tablespoon of lemon zest and ⅓ cup sugar together until fully combined and fragrant.
In a large bowl, combine 3 cups of flour, all of your lemon sugar, ½ teaspoon salt, 2½ teaspoons baking powder, ½ teaspoon baking soda and 1 Tablespoon Poppy Seeds.
Add the ¾ cup grated butter and cut with a pastry cutter or a fork, until the mixture looks coarse. (You should still see pieces of butter/flour "balls" about the size of small peas)
Make a well in the middle and add 1 cup of buttermilk. Mix until just combined. If the mixture is still dry, add 1–2 tablespoons extra buttermilk, but not any more than that. Don't over mix.
Transfer the dough to a floured surface and lightly knead into a ¾-inch-thick rectangle. Cut into triangles using a sharp knife. Place them on our prepared baking sheets. Space them out evenly, about ¼ inches apart.
Bake for 10-12 minutes or until lightly golden brown.
Place on cooling rack with parchment paper underneath to catch the glaze.