Preheat your oven to 400°F (200°C).

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

In a saucepan, melt the butter and brown sugar over medium heat, stirring until fully combined.

Once the mixture is boiling, continue to cook for about 3-5 minutes without stirring, until it becomes a light amber color.

Pour the hot toffee mixture over the Saltine crackers, spreading it evenly to cover them all.

Bake in the preheated oven for 5-7 minutes, until the toffee is bubbling.

Remove from the oven and immediately sprinkle chocolate chips over the hot toffee.

Spread the melted chocolate evenly over the toffee using a spatula.

If desired, sprinkle chopped nuts and a pinch of sea salt on top of the chocolate.

Allow the mixture to cool completely before breaking into pieces.