Heat oven to 350°F (325°F for dark and nonstick pan). Grease bottom only of 9-inch square pan with shortening or cooking spray. (For easier cutting, line pan with foil, then grease foil on bottom only of pan.) Make brownies as directed on box. Cool completely, about 1 1/2 hours. Cut into 4 rows by 3 rows to make 12 brownies.