For the scones:
1 1/4 cups (125 grams) all-purpose flour, plus more for forming scones
1 1/4 cups (185 grams) spelt flour (or all-purpose flour)
1/3 cup (65 grams) natural cane sugar (like turbinado)
1/4 cup (35 grams) poppy seeds, plus more to sprinkle on top
1 tablespoon baking powder
1/2 teaspoon baking soda
1 teaspoon kosher salt
6 tablespoons (85 grams) cold unsalted butter, cut into 1/2-inch cubes
3/4 cup plus 2 tablespoons buttermilk
1 large egg
1 teaspoon vanilla extract
2 tablespoons lemon juice
2 tablespoons fresh Meyer lemon zest
For the glaze:
1/2 cup powdered sugar, plus more if needed
1 1/2 tablespoons lemon juice, plus more if needed
Select a baking sheet that will fit inside your freezer; line it with parchment paper and set aside.
In a medium bowl, whisk together the flours, sugar, poppy seeds, baking powder, baking soda, and salt. Add the cubed butter. Using your hands or a pastry cutter, rub or cut the butter into the flour mixture until it resembles small, coarse peas. It’s okay to have a few larger chunks of butter remaining.
In a small bowl, whisk together the buttermilk, egg, vanilla extract, lemon juice, and lemon zest. Add to the dry ingredients. Using a wooden spoon or flat spatula, stir until the dough gathers together in an uneven ball (I actually use my hands at this point) — the dough will be pretty wet. Let the dough sit for 10 minutes to allow the whole-grain flours to soak up a bit of the moisture.
Take out a large wooden board (or use a clean table or counter) and sprinkle generously with flour before turning out the dough onto the surface. With well-floured hands, quickly gather the dough into a ball and pat or push it down so it’s circular in shape and about 1-inch thick. Cut into 8 wedges.
Place the wedges on prepared baking sheet and place in freezer. Freeze until firm, about 1 hour. Place scones in freezer bag and label. Store in the freezer until ready to bake.
To bake: Preheat the oven to 375°F. Line a baking sheet with parchment paper or a silicone baking mat. Arrange the scones so they're lying flat on the sheet, 2 to 3 inches apart. Bake for 25 to 30 minutes, or until tops are lightly brown. Cool on the pan for 5 minutes before transferring to a rack.
While cooling, prepare the glaze: Stir together the powdered sugar and lemon juice with a fork. Adjust consistency with a little more sugar or lemon juice as needed if too thick thin or thick.
Drizzle the glaze over the slightly warm scones with a fork or spread with a pastry brush. Sprinkle with the extra poppy seeds. Allow to cool completely before servi