2 1/4 c. flour
1/2 c. sugar
1/4 c. poppy seeds
1 t. cream of tartar
3/4 t. baking soda
1/2 t. salt
1/2 c. butter, chilled
1/4 c. orange juice
1 large egg
1/4 t. grated orange zest
1 egg white mixed with 1/2 t. water for glaze (optional)
Preheat oven to 375 degrees. Lightly butter a 10" diameter circle in center of a baking sheet.
Stir together the flour, sugar, poppy seeds, cream of tartar, baking soda, and salt. Cut the butter into 1/2" cubes and cut in with a pastry blender or two knives until mixture resembles coarse crumbs. In a small bowl, stir together the juice, egg, and orange zest. Add the juice mixture to the flour mixture and stir to combine. The dough will be sticky.
With lightly floured hands, pat the dough into a 9" diameter circle in the center of prepared baking sheet. If desired, brush the egg mixture over the top of the dough. With a serrated knife, cut into 8 wedges. Bake for 20-25 minutes, or until the top is lightly browned and a cake tester or toothpick inserted into the center of scone comes out clean.
Remove the baking sheet to a wire rack and cool for 5 minutes. Using a spatula, transfer the scones to the wire rack to cool. Recut into wedges, if necessary. Serve warm, or cool completely and store in an airtight container.
Serve with citrus curd and whipped cream.