Line a small cookie sheet with waxed paper or use Crisco shortening to grease pan
In a metal or glass mixing bowl, combine chocolate chips and butter making sure every morsel is covered in butter, set aside next to lined cookie sheet
Combine evaporated milk, sugar, and marshmallows in a saucepan
Cook above mixture over low heat stirring constantly until bubbling
Once bubbling, use a timer to continue stirring for six minutes on low heat
When the six minutes is over, turn off heat on stove, and quickly add the vanilla to the stovetop mixture and stir
Acting quickly, pour marshmallow mixture into bowl with chocolate chips and stir very quickly (the chocolate chips should all melt with the heat of the mixture)
Spread smoothly onto the cookie sheet in desired thickness
Refridgerate for 2-3 hours to set fudge
Enjoy!