Mix sugar and water in a medium saucepan and turn the stove to medium-high heat
Allow sugar to dissolve, stir constantly
Once dissolved, allow to boil and caramelize. You'll see bubbling. Allow this to go for about 10 minutes. The mixture will thicken and start to turn amber.
Once thickened, remove from heat and add butter, stir until melted.
Slowly pour in the heavy cream and stir until combined
Add vanilla extract and salt.
Allow to cool in the pan for about 10 minutes, then transfer to a mason jar and let cool completely.