Preheat oven to 375 F and line a baking sheet with parchment paper. In a mixing bowl, whisk together flour, salt and baking powder. Add the pieces of cold butter and cut them into the powders using a pastry cutter or rub them into the flour mixture using your fingers. The mixture should turn into a coarse meal with small and medium lumps.
Mix in the cheese and the scallions to the bowl. Combine the sour cream and eggs. Add them to the bowl and stir everything using a wooden spoon just until the mixture is moistened and a sticky, shaggy dough is formed.
Turn over the dough in a floured surface. Gather and pat the dough into a rectangle that is 10x2 inches in size. Divide the rectangle into 5 sections to form 5 smaller rectangles, then divide each rectangle in half diagonally to yield a total of 10 triangles.
Place them on the baking sheet with about an inch of space in between. Bake at 375 for 16-20 minutes, or until the scones are lightly golden. Store leftovers in a tightly covered container at room temperature.
Recipe adapted from King Arthur Flour.