In a medium bowl, stir together flour and powdered sugar.
Use a pastry blender, cut in the butter until the mixture resembles course crumbs.
Gently knead into a ball. (Using your hands works best and will help to melt the butter. The mixture will seem really crumbly at first. Keep working it.)
Roll the dough onto a lightly floured surface.
Cut into desired shapes. Roll the dough out again until it has all been used.
Bake for 15-18 minutes or until the edges begin to brown. Cool for five minutes before transferring to wire racks to cool completely.
Notes
Store in an airtight container at room temperature for up to one week or freeze for up to three months. This is the pastry blender I use.