Ingredients
2 1/2 cups all-purpose flour (spooned and leveled), plus more for work surface
1/4 cup granulated sugar
1 tablespoon baking powder
1/2 teaspoon coarse salt
1/2 cup (1 stick) cold unsalted butter, cut into small pieces
1/2 cup plus 2 tablespoons buttermilk
1 tablespoon finely grated orange zest plus 1/4 cup orange juice (from 1 orange)
1 large egg yolk
1 1/2 teaspoons poppy seeds
Coarse or sanding sugar, for sprinkling
Butter and fruit jam (optional), for serving
Preparation
Preheat oven to 400 degrees, with racks in upper and lower thirds. In a large bowl, whisk together flour, granulated sugar, baking powder, and salt. With a pastry blender or your fingertips, work butter into flour mixture until mixture resembles coarse meal, with a few pea-size pieces of butter remaining. With a fork, stir in 1/2 cup buttermilk, orange zest and juice, egg yolk, and poppy seeds until just combined.
On a lightly floured surface, turn out dough and knead several times. Form dough into a 7-inch square; cut into 9 squares, then cut each in half diagonally. Transfer dough triangles to 2 parchment-lined rimmed baking sheets. Brush tops with 2 tablespoons buttermilk; sprinkle with coarse sugar. Bake until scones are pale golden, 15 to 17 minutes, rotating sheets halfway through. Let cool on wire racks. Serve with butter and jam, if desired.
