Hi Melanie,
I have always had good luck replicating recipes. I would suggest taking a 14 ounce can of Sweetened and Condensed milk and some smooth/creamy peanut butter.......Maybe start out with a 1/3 cup of peanut butter and 1 tsp of vanilla. Combine in a saucepan over low heat. Keep stirring to get it nice and thick. Add more peanut butter if necessary to get the consistency you desire. Hope this helps. Let me know if it works!

Good luck!
Stacy