Preheat oven to 350°F. Line an 8x8 inch baking pan with aluminum foil, leaving a 2-inch overhang on all sides. Spray with cooking spray.
Place the sugar, condensed milk, and cookies in a food processor; process until smooth. Pour mixture into the prepared pan.
Bake for 30 to 35 minutes, or until golden brown and set. Cool in pan on a wire rack for 1 hour. Use the foil overhang to lift fudge from pan.