Add the heavy cream to a small saucepan and heat until the cream begins to simmer. Do not boil. Set aside.
Add the sugar and water to a 3-quart (or larger) heavy bottomed stainless steel saucepan. Do not use a nonstick saucepan. Moisten all of the sugar by swirling the pan.
Bring the mixture to a boil over medium high heat and reduce the heat to medium. Avoid the temptation to stir. The sugar will melt and the liquid will be clear.
After several minutes (depending on your stovetop and the pan you’ve chosen), the sugar mixture will change from clear to light amber.
The color will continue to darken as the water evaporates and the temperature rises. Keep a very close eye on your caramel at this point as it can move from light to dark fairly quickly, and burn.
Once the caramel reaches a dark amber color, carefully and slowly pour the heavy cream into the boiling sugar, while stirring with a wooden spoon. (If you are more comfortable, you can remove the pan from the heat source, stir in the heavy cream, and return to the heat).
Stir in the diced butter. Continue to cook caramel for 1 to 2 minutes, while constantly stirring.
Remove from the heat. Stir in the vanilla paste and sea salt.
Allow to cool slightly before transferring to an airtight container. Store in the refrigerator for several weeks.