Combine brown sugar, cream, corn syrup and salt in a large sauce pan. Bring to a boil over medium-low heat, stirring regularly. Add butter and let mixture low boil while stirring for 5-6 minutes or until it reaches 236- 240 degrees Fahrenheit using a candy thermometer or when mixture forms a ball when dropped in a measuring cup of cold water.
Remove from heat and fold in pecans and vanilla with a wooden spoon. Stir constantly until candy begins to thicken (about 3-4 minutes). When it becomes the consistency of melted peanut butter, quickly drop heaping spoonfuls onto parchment paper to set.
Let stand 30 minutes or until firm. Should be the consistency of fudge when ready.
