Preheat your oven to 350 °F. Line a 9×13-inch baking dish with foil and lightly coat it with non-stick cooking spray.

Arrange the graham crackers in a single layer in the pan so the bottom is covered (break some crackers if needed to fill spaces). A few slight gaps are fine. Set aside.

In a medium heavy‑bottomed saucepan with high sides, add the butter, brown sugar, and salt. Heat over medium‑high until the butter melts, stirring constantly.

Once melted, allow the mixture to boil for about 4½–5 minutes (lots of bubbles) while stirring constantly to avoid burning; it should thicken to a caramel‑like consistency.

Evenly drizzle the hot toffee mixture over the layer of graham crackers, making sure to cover them completely.

Bake for about 7 minutes, or until you see bubbling around the edges of the layer.

Remove the pan from the oven, sprinkle the chocolate chips evenly over the hot toffee layer, then return the pan to the oven for about 2 minutes (or until the chocolate is glistening and soft).

Use a spatula to smooth out the melted chocolate into an even layer.

Sprinkle the toffee bits evenly on top of the chocolate layer.

Let the bars cool for about 2–3 hours (or until the chocolate has fully set) before slicing into pieces. (If you’re in a hurry you can refrigerate, but it may cause condensation.)