Toasted Marshmallow K-Bars

Bahan-bahan (24 porsi)

• 1/2 cup (1 stick) salted butter, at room temperature
• 1 bag (10 ounce) mini marshmallows
• 1 cup creamy peanut butter
• 5 cups Corn Flakes or Rice Krispies cereal
• 2 cups regular marshmallows
• 20 ounces semi-sweet/dark chocolate, melted
• flaky sea salt ((optional))