In a medium saucepan over medium heat, whisk together cream, corn syrup, brown sugar, cocoa powder, and salt until smooth.

Stir in half of the chopped chocolate (3 oz) until melted. Bring just to a low boil, stirring frequently.

Reduce heat to medium‑low and cook 3–5 minutes, stirring often, until the mixture thickens slightly.

Remove from heat and stir in remaining 3 oz chocolate, butter, and vanilla until glossy and fully melted.

Serve warm over desserts—or let cool slightly and store in an airtight jar in the fridge; reheat gently before re‑serving.