Next, bring mixture to boil stirring occasionally (about 5 mins). Remove pan from heat then add chocolate chips and vanilla. Stir until melted and combined, if you'd like add 1/2 cup of add-ins such as peppermints, walnuts or candies.
Pour the hot fudge into loaf pan.
Top with remaining "Add-Ins" and let set for 3 hours at room temperature.
Grip wax paper and lift out of pan, placing on a cutting board to slice.