Line a 9x9 pan with aluminum foil and butter the inside. Set aside.

Fill a large bowl with ice water and set aside.

In a large saucepan combine cream and sugar and bring to a boil over medium heat stirring constantly. Once it begins to boil cook until it reaches 242 Degrees F on a candy thermometer. (soft ball stage). Remove from heat and add the butter and vanilla. Place saucepan in the ice water to cool and stir until it becomes thick and has lost its sheen. Spread mixture in 9x9 pan and cover top with a piece of was paper. Place in a cool dark place to harden. Once it has set lift out of pan by grasping the edges of the aluminum foil. Cut into squares and store in a covered container separating each layer with a piece of wax paper.