Step 1

Line a 9x13-inch baking pan with parchment paper, leaving an overhang on the sides.

Step 2

Spread the crushed pretzels evenly in the prepared pan. Press them down gently to create a firm base.

Step 3

In a medium saucepan, combine the sweetened condensed milk, butter, and brown sugar. Cook over medium heat, stirring constantly, until the mixture is smooth and slightly thickened (this should take about 3-5 minutes).

Step 4

Pour the caramel mixture over the pretzels and spread it evenly.

Step 5

Pour the melted chocolate over the caramel layer and spread evenly. Sprinkle with sea salt flakes, if desired.

Step 6

Refrigerate for at least 2 hours, or until the bars are completely firm.

Step 7

Once firm, lift the bars from the pan using the parchment paper overhang. Cut into squares and serve.