In a saucepan, combine and melt cream, butter, sugars and salt.
Simmer for 45 seconds.
Add chocolate chips and stir to dissolve
Add cocoa and whisk up that mixture until smooth.
On low, let the sauce simmer for up to five minutes. (The original recipe says 20 seconds so play with it...simmering longer helped it to firm up a bit for me.) Be sure not to let it boil.
Serve over ice cream or cake or cookies...any favorite dessert. Or, you can always just eat it with a spoon. It's that good!
Notes
This sauce can be stored in the fridge for a couple weeks or in the freezer for months. Just thaw and warm when you are ready to use it.