Unsweetened natural cocoa powder is the base for this sauce. Natural cocoa powder, albeit lighter in color than Dutch-processed cocoa, has a more chocolaty flavor.
This chocolate sauce can be used atop a scoop of ice cream, or drizzled over a wedge of cake or a plate of crepes or waffles. You can use it to dip strawberries... Or to make my Dark Varietal Chocolate Drink.
Sift the cocoa powder into a small bowl.
Put the sugar, cream, corn syrup, water, vanilla extract, and salt in a medium heavy bottomed saucepan. Scrape the seeds from the vanilla bean into the pan. Place over medium heat and whisk until all the ingredients are blended. Add the cocoa powder. Reduce the heat to low and whisk constantly. The sauce will get lumpy, but then become smooth as it cooks. Cook until it just begins to boil. This should take about 8 minutes. Be careful that it does not burn.
Pour the sauce into a 1-quart clear vessel. Blend with an immersion blender until smooth.
Either use immediately, or pour the finished sauce into a bowl, let cool to room temperature, pour into a jar, cover, and refrigerate. It will keep for at least 1 month. To reheat, stir over low heat.