Line a 9x13 baking dish with wax paper and spray with cooking spray. Don't skip the cooking spray or the toffee may stick to the wax paper.
Place the saltines on the wax paper in a single layer.
24 saltine crackers
Mix the peanuts, ½ cup of golden (or corn) syrup, and sugar in a bowl and microwave for approximately 2 minutes. Stir and continue to microwave until the sugar melts and the mixture begins to bubble.
1 ½ cups lightly salted peanuts, ½ cup +1 tbsp golden syrup, 1 cup granulated sugar
Add a tablespoon of butter and vanilla to the mixture and stir until melted. Microwave until the mixture browns, about 2 minutes.
5 tbsp unsalted butter, 1 tsp vanilla extract
Quickly pour the hot mixture over the crackers and spread evenly with a rubber spatula. The mixture is going to be very sticky and hot so spread it quickly before it begins to harden.
Refrigerate the crackers for an hour.
Remove the saltine toffee from the dish and break it apart using your hands or a knife. Place the toffee pieces back in the baking dish.
Combine chocolate chips, 4 tablespoons of butter and 1 tablespoon of syrup in a bowl. Microwave in 30-second intervals, mixing in between, until the chocolate is melted.
5 tbsp unsalted butter, ½ cup semi-sweet chocolate chips, ½ cup +1 tbsp golden syrup
Use a spoon to drizzle the chocolate mixture over the toffee. Once the chocolate hardens, your saltine cracker toffee is ready to serve!