Spray an 8-inch square cake pan with nonstick spray.

Add the butter to a medium saucepan over medium-high heat. Once melted, stir in the brown sugar, heavy whipping cream and corn syrup. Cook until thick and syrupy while stirring frequently, about 7 minutes. Stir in the salt. Turn off the heat and stir in the marshmallows. Keep stirring until the marshmallows are smooth and melted. Add the cereal to the pan and gently fold until all cereal is coated. Add the Mallow Bits and gently fold into cereal mixture until evenly distributed throughout the mixture.

Pour into the prepared pan and press down with a piece of parchment paper sprayed with nonstick spray. Sprinkle lightly with flaky sea salt.

Drizzle melted chocolate over the top of treats. Cool completely, and then cut into squares.