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Prepare a shallow baking sheet by lining it with parchment paper.  Alternatively, you could lightly grease the pan with butter, shortening, or nonstick baking spray instead of using parchment paper. If you have a nonstick baking mat, you could use that instead of a prepared baking sheet. Stir the three ingredients together in a medium to large mixing bowl until thoroughly combined. If desired, you could replace half of the all-purpose flour with whole wheat flour. Slice the butter into 1/2-inch (1.25-cm) cubes before tossing them into the flour mixture. Blend them into the flour using a pastry blender until large, coarse crumbs form.  The crumbs should be about the size of a pea. If you do not have a pastry blender, you could cut the butter into the flour mixture by using two knives to stir and chop the butter while immersed in the flour mixture. Pour the milk in, stirring it into the dry ingredients until moistened.  Use a fork or spatula to stir. Stop as soon as the dry ingredients are moistened. Over-mixing the dough could create tough, chewy biscuits. Turn the dough onto a clean, lightly floured surface and knead several times until the dough sticks together.  Gently pat the dough into a rounded or rectangular shape. At this point, the dough should be about 3/4 inch (2 cm) thick. Fold the dough into three sections in order to create biscuits that have multiple, flaky layers. Overlap the ends over the center of the dough, creating a brochure-style fold. After folding the dough, flatten as usual to the specified thickness. Use a round, 3-inch (7.5-cm) biscuit cutter with sharp edges to cut out rounds of dough. Place the biscuits onto your prepared baking sheet, spacing them about 1 inch (2.5 cm) apart.  A cookie cutter or the mouth of a glass could be used in the absence of an actual biscuit cutter. After your first batch of biscuits has been cut out, pat the scraps together again so that you can cut out more biscuits from the remaining dough. Continue until all the dough has been used. While circular biscuits are the most traditional shape, you could cut your biscuits into any shape desired. Cutting the biscuits into squares will prevent you from having to roll out any excess dough. Alternatively, create drop biscuits by dropping rounded tablespoons of dough onto your baking sheet. This will create biscuits that are more rustic in appearance. The biscuits should be a light, golden brown when done. Note that if you opted to form drop biscuits instead of cut biscuits, the peaks of dough will be slightly darker and crispy when the biscuits are done. The biscuits can be served immediately, or you can let them cool slightly on a wire rack for a few minutes first. Use oven mitts or a thick dish towel when removing the biscuits from the oven.
Preheat the oven to 425 degrees Fahrenheit (218 degrees Celsius). Combine the flour, baking powder, and salt. Cut and put in the butter. Add the milk. Knead the dough. Cut out biscuits. Bake the biscuits for 15 to 18 minutes. Serve warm.