In a large bowl, beat the butter, salt and baking powder until blended. Gradually add flour and mix just until crumbly. Store in an airtight container in the refrigerator for up to 1 month. Quick Cookie Mix may be used to prepare the following recipes: Apricot Thumbprints, Butter Almond Cookies, Peanut Butter Blossoms and Toffee Triangles. Yield: 8 cups.