In large saucepan melt butter over low heat. Add 4 cups marshmallows and stir until completely melted. Remove from heat. Stir in peanut butter until melted.
Stir in Rice Krispies and remaining 2 cups of mini marshmallows until well coated. Press into a greased 9×13 pan and set aside.
Place caramels and heavy cream into a small bowl. Microwave in 20-30 second intervals until completely melted. Pour overtop Krispie treats and spread until mostly covered. Sprinkle with sea salt and cool.
Cut into bars using a sharp knife and serve. Store in airtight container for up to 5 days.
Calories: 257kcal | Carbohydrates: 44g | Protein: 4g | Fat: 7g | Saturated Fat: 2g | Cholesterol: 10mg | Sodium: 890mg | Potassium: 116mg | Sugar: 27g | Vitamin A: 855IU | Vitamin C: 7.2mg | Calcium: 34mg | Iron: 3.7mg