1 3/4 c. Swan's Down cake flour
1/3 c. sugar
1 1/2 tsp. baking powder
3/4 tsp. baking soda
1/2 tsp. salt
3/4 c. (1 1/2 sticks) chilled unsalted butter, cut into pieces
1 1/3 c. rolled oats
1/2 c. dried currants
10 tbsp. (or more) chilled buttermilk
1 egg, beaten to blend (glaze)

Preheat oven to 375 degrees. Line cookie sheet with parchment. Combine first 5 ingredients in processor. Add butter and cut in until mixture resembles fine meal. Transfer to large bowl. Mix in oats and currants. Add buttermilk and mix just until dough comes together, adding more buttermilk by tablespoons if dry. Turn dough out onto floured surface. Pat into 1 inch thick round. Cut out rounds using 3 inch cookie cutter. Gather scraps; pat into 1 inch thick round. Cut out more scones. Transfer scones to prepared cookie sheet, spacing 3 inches apart (scones will spread during baking). Brush generously with egg glaze. Bake scones until brown, about 30 minutes. Cool slightly on rack. Serve scones warm.