1 cup granulated sugar
1/2 cup salted butter (not margarine)
1 (5-oz) can evaporated milk (2/3 cup)
1 1/2 (12-oz) packages white chocolate chips (3 cups)
1 (7-oz) jar marshmallow cream or 1 (10-oz) package mini marshmallows
3 cups coarsely crushed Oreo cookies (about 25 cookies), divided
1. To make it easy to remove fudge and cut into small pieces, line a 9-inch square baking pan with aluminum foil and spray lightly with cooking spray.
2. Stir together sugar, butter, and milk in a medium-size saucepan. Cook over medium heat, stirring constantly, until mixture comes to a rolling boil. 3 minutes without stirring. Set a timer; don't guess. Remove from heat and add white chocolate chips and marshmallow cream; stir until both have melted and mixture is smooth. Gently stir in 2 1/2 cups crushed cookies.
3. Pour fudge in prepared pan and spread to the edges of the pan. Sprinkle remaining 1/2 cup crushed cookies over warm fudge and press down gently with fingertips. Let cool completely on a wire rack (about 2 hours). You can speed this up by placing in the refrigerator. Cut into 48 pieces (8x6).