1 cup butter (2 sticks)
1 1/3 cup packed brown sugar
About 40 unsalted saltine crackers (that's the secret!)
1 bag of semisweet chocolate chips
1 cup finely chopped walnuts or toasted almonds (if you so desire- I leave these out)
Preheat your oven to 375 degrees. Line your pan (I use 11 x 17, but if you cut the recipe in half, it should work for 9 x 13 pans as well) with foil- make sure it goes up on the sides too.
Melt butter in a saucepan and then add the brown sugar and mix until the sugar melts. It should be syrupy. Pour into your foil-lined pan and make sure it spreads out evenly. Layer the saltines on top.
Next, pop it into the oven for 10 minutes. When you take it out, pour the chocolate chips on top evenly and put it back into the oven for another minute. When you remove it, the chocolate should be soft- spread it across the crackers so that everything is covered.
Put it in the refrigerator for at least an hour (probably longer). When you take it out, you can just lift the foil and break the toffee into chucks.
Refrigerate for storage. Not that it'll be around for that long...