Chocolate syrup which gets thicker when it gets cold -- like when you pour it on ice cream. It is not just heated-up chocolate syrup. It helps to make any sundae or banana split -- or even cheesecake -- more delicious.
You can buy this at the grocery store, or you can make it yourself. First, get yourself two cups of semisweet chocolate chips, a cup of butter, four cups of confectioners sugar, 2 2/3 cups of evaporated milk, a teaspoon of vanilla or vanilla extract, and 1/8 teaspoon of salt.
Next, get a large saucepan, put in the chocolate chips and butter, turn the burner on low, and stir them together 'til they're melted. Then mix in the sugar and canned milk, and increase the heat 'til the whole mixture is boiling. Keep it stirring for about eight minutes, then take it off the heat, and stir in the vanilla and salt. SHAZAM! It's finished!
Pour it over your ice cream while the sauce is still warm. Marvel over how thick the sauce gets and how divine it tastes. Put any of it you don't use into the refrigerator, and just pop it into the microwave when you're ready for another snack.