In a large saucepan and over medium heat mix together water and granulated sugar. Cook until sugar has turned into an amber color, roughly 10 to 12 minutes.
Slowly add in butter, being careful so the sugar doesn’t splatter. Use a whisk and cook for roughly 2-3 minutes.
Very slowly add the heavy cream, stirring constantly. Allow mixture to boil for about 1 minute more. It will rise as it boils so keep an eye on it.
Remove from heat and stir in salt and vanilla. Allow to cool before using.
Once cooled, but pourable, pour oven cool brownies. Sprinkle with coarse salt if desired
