Preparation Steps

• Grease an 8x8 inch baking pan and line with parchment paper, leaving an overhang on the sides.
• In a large saucepan, combine butter, granulated sugar, brown sugar, evaporated milk, and corn syrup. Cook over medium heat, stirring constantly, until sugar is dissolved.
• Bring the mixture to a boil, then reduce heat to low and simmer for 5 minutes, stirring occasionally.
• Remove from heat. Stir in vanilla extract, chocolate chips, and marshmallows until melted and smooth.
• Pour the mixture into the prepared baking pan and spread evenly. If desired, sprinkle with flaky sea salt.
• Let the fudge cool completely at room temperature, or chill in the refrigerator for about 2 hours until firm.
• Once firm, lift the fudge out of the pan using the parchment paper. Cut into 16 squares.