1Place foil in bottom and over sides of 9" square pan, leaving enough foil on sides to lift fudge when firm.
Cut cream cheese into small cubes. Rinse and drain blueberries.
2Combine butter, sugar, evap milk and marshmallow cream, and bring to rolling boil over medium heat.
Boil for 5 minutes, STIRRING CONSTANTLY. don't stop stirring!
(As Jo Anne notes: don't turn your back on it!)
Remove from heat and stir in cream cheese and white chocolate chips until melted and mixture is smooth.
Carefully stir in blueberries and vanilla.
3Pour into pan and let cool. Refrigerate until firm, at least 2 hours.
4Using foil "handles," lift from pan and place on cutting board.