- In a medium saucepan, mix brown sugar, corn syrup, water, butter, and salt together. Over medium heat, bring the mixture to a boil, do not stir, and let it cook until it reaches 236°F (soft ball stage).
- Remove from heat and cool mixture to lukewarm.
- Stir in cream and vanilla.
- Pour into a heatproof jar and store in the refrigerator. Use within one month.
- To reheat before serving, pour into saucepan and warm over low heat; or set jar in a small pot of simmering water.