Place water and corn syrup in small saucepan and stir over medium heat. Add sugar and gently stir. Swirl pan often as the sugar melts and begins to caramelize. This will take about 10 minutes.

Meanwhile, heat the heavy cream in microwave. Once the sugar has turned a dark amber color, reduce the heat to low and gently stir in the heavy cream, a little at a time. Add the butter, cocoa powder, and salt, and allow to melt completely, while gently whisking.

Once the butter has melted, gently whisk the mixture until it is well combined. Remove from the heat, and let cool to room temperature before moving to an airtight container.

Store in the refrigerator for up to 1 week.