The Harlem Tea Room's Scones
8 Tbsp (1 stick) cold, unsalted butter, cut into small pieces, plus extra for baking sheets
3 1/2 cups all-purpose flour
2 tsp baking soda
2 tsp cream of tartar
1/2 tsp salt
1 1/2 cups sour cream or buttermilk
1 egg, beaten, or milk for brushing scones
Preheat oven to 450. Coat 2 baking sheets with butter. Sift flour, baking soda, cream of tartar, and salt into a large bowl. Add butter, using fingertips to combine until mixture takes on texture of fine meal. Add sour cream and stir until flour mixture is just moist and dough begins to stick together. Gather dough into a ball and knead lightly until fully integrated.
Place dough on a floured work surface and roll with a floured rolling pin to 3/4-inch thick. Dip a 2-inch cutter into flour and cut out scones as close to one another as possible. Place on prepared baking sheets, with space in between; let stand 10 minutes. Brush tops with egg, and bake until golden brown, 10 to 12 minutes. Remove to wire rack to cool. Serve warm with butter, clotted cream, fruit preserves, or jam.
Baking powder scones: Omit baking soda and cream of tartar and subsitute 4 tsp baking powder to dry ingredients. Replace sour cream with 1 1/4 cups milk.
Cheddar-thyme scones: After combining butter and dry ingredients, stir 1 1/2 cups grated Cheddar cheese and 1Tbsp chopped fresh thyme into flour mixture before adding sour cream. Sprinkle tops of scones with an additional 1/2 cup grated Cheddar cheese before baking.
Raisin scones: Add 1/4 cup sugar to dry ingredients. After combining butter and flour mixture, stir in 1 cup raisins