1/2 cup (125 ml) plus 1 tablespoon buttermilk
1 large egg
1 cup (128 grams) whole wheat pastry flout
1 cup (135 grams) all purpose flour
1/4 cup (47 grams) natural cane sugar
1 tablespoon (14 grams) baking powder
1/4 teaspoon (2 grams) fine sea salt
1 tablespoon (11 grams) poppy seeds
Freshly grated zest of 1 lemon
6 tablespoons (3 ounces) very cold butter, cut into 12 pieces
Preheat the oven to 425ºF.
Using a fork, lightly beat 1/2 cup of the buttermilk and egg together in a small bowl; set aside.
Add the flours, sugar, baking powder, salt, poppy seeds and lemon zest to a deep medium-sized bowl. Whisk to combine. Add the butter and rub together quickly with your fingers, until it forms a sandy-looking texture with some pebble-sized pieces. Pour in the buttermilk-egg mixture, and use a fork to stir together until it forms a crumbly-looking dough.
Turn the dough out onto a lightly floured counter. Knead it once or twice to give the dough a smoother appearance. Divide the dough and shape into two 1/2-inch thick rounds. Use a sharp knife to cut each round into 6 triangles (as if cutting a pizza).
Place the scones on an ungreased baking sheet, and brush with the remaining tablespoon of buttermilk. Bake for 12 minutes, until bottoms are lightly browned and the tops are golden. Remove from oven and set tray on a wire rack to cool a few minutes before serving. Leftovers may be stored in an air-tight container and heated in the toaster the next day.