Prepare the Shortbread Base:

• Preheat the oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper or grease it lightly.
• In a mixing bowl, cream the butter and sugar until light and fluffy. Gradually add the flour and salt, mixing until a crumbly dough forms.
• Press the dough evenly into the prepared pan and bake for 20–25 minutes, or until the edges turn golden brown. Let it cool.

Craft the Caramel Layer:

• In a medium saucepan, melt the butter over medium heat. Add the brown sugar and stir until dissolved.
• Stir in the sweetened condensed milk and bring to a gentle boil. Reduce heat to low and cook for 8–10 minutes, stirring constantly until thickened and golden.
• Remove from heat and stir in the vanilla extract. Pour the hot caramel evenly over the cooled shortbread base and spread it smoothly with a spatula. Let it cool for 30 minutes.

Add the Chocolate Topping:

• Melt the chocolate chips in a microwave-safe bowl in 30-second intervals, stirring between each, until smooth.
• Pour the melted chocolate over the caramel layer and spread it evenly. Sprinkle with optional toppings like sea salt or chopped nuts.
• Refrigerate for 1–2 hours or until the chocolate is fully set.

Cutting and Serving:

• Use the parchment paper to lift the dessert out of the pan. For clean cuts, use a warm, sharp knife and slice into squares or rectangles.
• Allow the squares to come to room temperature before serving for the best texture.