Preheat your oven to 400°F (200°C).

Heavily line a rimmed 10x15 inch baking sheet with heavy-duty aluminum foil, ensuring the foil comes up and over the edges. Spray the foil generously with non-stick cooking spray.

Arrange the saltine crackers in a single, flat layer covering the bottom of the prepared pan.

In a medium saucepan, combine the unsalted butter and packed light brown sugar. Melt over medium heat, whisking constantly until combined.

Bring the mixture to a rapid, rolling boil. Once boiling across the entire surface, set a timer for exactly 3 minutes. Do not stir it while it boils.

The exact second the 3-minute timer goes off, remove the pot from the heat and carefully pour the hot caramel evenly over the crackers. Quickly spread it with a spatula to ensure all crackers are covered.

Place the pan in the preheated oven and bake for 5 minutes.

Remove the pan from the oven and immediately scatter the semi-sweet chocolate chips evenly over the bubbling toffee.

Let the pan sit undisturbed for 3-5 minutes until the chocolate softens. Use a spatula to spread the melted chocolate into a smooth, even layer.

Immediately top with holiday sprinkles or crushed pecans while the chocolate is still wet.

Allow the pan to cool on the counter for 30 minutes, then transfer to the refrigerator for 2 hours to harden completely.

Once the candy is rock hard, peel away the foil and break the toffee into rustic shards.