Melt butter and 24 caramels in a large saucepan over medium heat, stirring constantly.
Stir in marshmallows, chocolate chips, and vanilla, remove from heat and continue stirring until fully melted.
Pour the mixture into the baking pan.
Place the last 10 caramels in a microwave safe bowl, microwave for 30 seconds at a time until the caramels are melted. Drizzle the caramel over the fudge.
Allow to set, then cut into one-inch squares, store in an airtight container for up to a week.