Preheat oven to 425° Fahrenheit. Line jelly roll pan(s) with aluminum foil, then lightly spray foil with neutral cooking spray.
Arrange 35-40 saltine crackers salt-side down in single layer on top of aluminum foil. Set pan aside.
Place medium saucepan on stovetop over medium heat. Add 1 cup unsalted butter to saucepan and let butter melt completely.
Once butter begins to melt, add 1 packed cup light brown sugar to saucepan. Gently whisk sugar into butter, then increase heat under saucepan to medium-high.
While whisking constantly, bring butter-sugar mixture to boil, then allow mixture to boil 2 to 3 minutes or until mixture develops light caramel color.
Once mixture develops light caramel color, remove saucepan from heat. Carefully pour mixture into jelly roll pan(s), covering saltine crackers completely. Distribute caramel layer as evenly as possible.
Once crackers are completely covered with caramel, carefully place jelly roll pan(s) in oven. Bake caramel-covered crackers approximately 3 to 5 minutes, watching caramel closely.
While caramel-covered crackers are baking, place 5-10 saltine crackers in sealable, food-safe plastic bag. Seal bag and crush crackers into small pieces. Be careful not to crush crackers into powder. Set crushed crackers aside.
When caramel just begins to bubble, remove jelly roll pan(s) from oven.
Immediately sprinkle 8 ounces chocolate chips evenly over caramel layer. When chocolate chips begin to melt, use butter knife or offset spatula to spread melting chocolate over caramel layer, covering caramel completely.
Let chocolate set slightly, then sprinkle crushed saltine crackers evenly over chocolate layer. If needed, gently press saltine pieces into chocolate layer to help pieces stick.
Place jelly roll pan(s) in freezer. Freeze toffee 15 to 20 minutes or until sheet of toffee is very cold.
When toffee is cold, remove pan(s) from freezer. Use knife or hands to break sheet of toffee into pieces of desired size.
Let toffee pieces come to room temperature, then serve.