Preheat oven to 350°F (175°C). Line a rimmed baking sheet with parchment paper or aluminum foil, then arrange the saltine crackers in a single layer, covering the entire surface.

In a medium saucepan, melt the butter over medium heat. Stir in the brown sugar and bring to a rolling boil. Boil for 3 minutes without stirring, ensuring the sugar dissolves fully and the mixture thickens.

Immediately pour the hot caramel mixture evenly over the saltine crackers, spreading it gently with a spatula to cover all crackers.

Bake in the preheated oven for 5 minutes until bubbly.

Remove from oven and sprinkle the chocolate chips evenly over the hot caramel. Let sit for 5 minutes to allow the chocolate to soften.

Using a spatula, spread the melted chocolate evenly over the caramel layer.

If desired, sprinkle chopped pecans or walnuts and a light pinch of sea salt on top.

Refrigerate the baking sheet for at least 2 hours or until the chocolate is set and the candy is firm.

Once set, break into pieces and serve or store in an airtight container.