In a medium saucepan, combine the sugar and water, stirring to ensure all the sugar is covered with water.

Turn the heat on and cook on medium-high for about 8 minutes without stirring, until the syrup begins to turn amber colored.  Keep an eye on it, because how dark it gets determines how sweet it is, but you don’t want it to burn.

As soon as it’s a slightly dark amber color, add the heavy cream and lower the heat, stirring briskly so it doesn't harden. This will cause the caramel to bubble up, so do it carefully so you don't get burned.

Once it settles, add the butter, peanut butter, balsamic, vanilla, and sea salt.  Stir until you have a smooth caramel.  Taste to make sure the balance of flavors is good for you.

Pour into a heat-safe container and allow to cool and thicken a bit more.  Can be stored in the fridge (in an airtight container) for weeks.  When you want to use it again, warm it gently in the microwave and whisk to make sure it's not grainy.