This is the critical step that creates tender, flaky scones. Take your cold butter cubes and add them to the flour mixture. Using a pastry blender, two forks, or even your fingertips, work the butter into the flour until the whole mixture looks like coarse breadcrumbs or sand. Pieces of butter should still be visible—this is exactly what we want.
Why? As the scones bake, those little butter pieces create steam pockets, making the crumb tender and layered rather than dense. If you overmix here, you'll end up with tough scones that taste more like cake. Keep your touch light and your movements quick. If your kitchen is warm, work faster or chill your bowl for five minutes.