Originally from Silver Palate Cookbook
- Melt all the chocolate and butter very slowly in a double boiler or in the microwave, stirring frequently until combined. Meanwhile, heat the water to boiling in the small, heavy saucepan. When the butter and chocolate have melted, stir the mixture into the boiling water. Add the sugar, corn syrup and salt and mix until smooth. Turn the heat up and stir until mixture starts to boil; adjust heat so that sauce is just maintained at the boiling point, stirring occasionally. Allow sauce to boil for nine minutes.
- Remove from heat and cool for 15 minutes. Stir in the vanilla extract and serve warm over ice cream.
- Sauce can be easily and quickly reheated in the microwave for 15 to 30 seconds. Stir and it will be shiny and even again.