Line a 9×13-inch baking sheet with parchment paper or foil, making sure there’s a bit of an overhang so you can easily lift the toffee out later.
Arrange the Saltine crackers in a single layer on the baking sheet. You may need to break some crackers to fit the edges of the pan.
2. Make the Toffee:
In a medium saucepan over medium heat, melt the butter and brown sugar, stirring constantly. Bring the mixture to a boil, and let it boil for 3-5 minutes, stirring occasionally, until it thickens and becomes golden brown.
Remove from heat and stir in the vanilla extract, if using.
3. Pour the Toffee:
Carefully pour the hot toffee mixture over the Saltine crackers, spreading it evenly to cover all of them. Use a spatula to gently spread the toffee if necessary, ensuring the crackers are all coated.
4. Bake:
Place the baking sheet in the preheated oven and bake for 5-7 minutes, or until the toffee is bubbly and golden. Be sure to watch carefully so it doesn’t burn.
5. Add the Chocolate:
Remove the pan from the oven. Immediately sprinkle the chocolate chips evenly over the hot toffee. Let the chocolate sit for a few minutes to melt, then spread it into an even layer over the toffee using a spatula.
6. Chill:
Let the toffee cool at room temperature for about 15 minutes, then transfer it to the refrigerator to cool completely for about 1-2 hours, until the toffee is firm.
7. Break Into Pieces:
Once the toffee has chilled and set, lift it out of the pan using the parchment paper or foil overhang.
Break it into pieces using your hands or a knife.
8. Serve or Store:
Serve immediately, or store the Saltine toffee in an airtight container at room temperature for up to one week or in the refrigerator for longer storage.
