Line a 9 inch square pan with foil, long enough to extend over 2 sides (to use as handles); spray with cooking spray.
In a large mixing bowl, add marshmallow fluff and white chocolate chips. Set aside.
Combine sugar, cream and butter in saucepan, cook on medium heat, stirring once or twice until mixture reaches 235°F.
Remove from heat and immediately pour hot cream mixture into bowl with marshmallow and chips. Stir well with wooden spoon - mixture will appear slightly stretchy and unappetizing, but don't worry, it will smooth out.
Remove 1 cup of mixture and set aside.
In large bowl with remaining mixture, stir in orange extract and a few drops of each food color until mixture reaches a lovely orange color. Adjust colors if needed. Pour into prepared pan.
Pour or spoon white mixture on top of orange. Drag a knife through both to make swirls. Using a sheet of plastic wrap sprayed with cooking oil, press down slightly to smooth top.
Let cool to room temperature, about 40 minutes. Then chill for one hour or until set. Lift fudge from pan using foil handles and using a large knife, cut into squares.