Melt 4 tablespoons of unsalted butter in a large saucepan over low heat. Add 10 ounces of marshmallows and stir until melted and smooth (about 3-5 minutes). Mix in a pinch of salt and fold in 6 cups of Rice Krispies until coated.

Lightly grease a 9x13-inch baking dish, transfer the Rice Krispie mixture, and press down evenly with a greased spatula. Cool for about 30 minutes at room temperature.

In a medium saucepan, combine 1 cup of granulated sugar and heat over medium-low, stirring until it dissolves and turns deep amber (5-7 minutes). Quickly add 6 tablespoons of butter, then 1/2 cup of heavy cream, and mix in 1 teaspoon of sea salt, letting it cool slightly.

Drizzle the warm salted caramel sauce over the Rice Krispie mixture. Add more caramel for sweetness and sprinkle more sea salt if desired.

After about 10-15 minutes, cut into squares and serve on a platter. Store in an airtight container for up to three days.