Combine sugar, corn syrup, butter and vanilla in a small saucepan over medium heat.
Bring to a boil and continue to cook until temperature reaches 220 degrees F. Stirring is not required, just set your timer and wait! It takes approximately 8 minutes on my stovetop.
When the sugar mixture reaches 220, remove from heat and add salt and heavy cream. Stir with a whisk until completely combined.
Let cool to room temperature and pour into an airtight jar. It makes a little more than 1 ¼ c or 10oz. It will thicken slightly as it cools.