Preheat the oven to 400°F (200°C).

Line a baking sheet with parchment paper and arrange the Saltine crackers in a single layer.

Melt the butter and brown sugar in a saucepan over medium heat, stirring occasionally.

Once the mixture boils, let it cook for 3-4 minutes without stirring, until it’s a deep caramel color.

Pour the hot toffee mixture over the arranged Saltine crackers, spreading it evenly with a spatula.

Bake in the preheated oven for 5-6 minutes until bubbly and golden.

Remove from the oven and immediately sprinkle the chocolate chips evenly over the surface.

Once the chocolate is melted, spread it evenly across the toffee layer.

Sprinkle with chopped nuts and a dash of sea salt, if desired, before the chocolate hardens.

Let the entire sheet cool completely at room temperature before breaking into pieces.