6 Tbsp butter, melted (I add chunks un-melted with the marshmallow cream instead – see pictures)
1/4 tsp salt
Butter a large cookie sheet. Scatter peanuts equally on cookie sheet.
Place marshmallow cream in a LARGE bowl, set aside.
In a large saucepan, combine corn syrup and sugar. Place over medium high heat. Stir constantly with a wooden spoon until mixture comes to a boil. Clip on candy thermometer. Cook to 280 degrees F, or to soft crack stage. (don’t stir during this time) Remove from heat and let stand 2 minutes undisturbed.
Without scraping, pour entire batch into marshmallow cream and stir with a wooden spoon until smooth. Add butter, vanilla, and salt and stir with wooden spoon until butter in incorporated.
Pour into prepared pan and spread evenly across peanuts.
Allow to stand at room temperature until firm, about 3 hours. Cut and wrap in wax paper.