In a heavy bottomed sauce pan/pot, add your sugar. Over medium heat melt the sugar stirring constantly. As the sugar melts it will start to clump before it gets smooth. This is normal. (2 cups white sugar)
Once it’s melted, continue stirring, and allow it to become an amber color and start to have a nutty smell. Be careful not to let it go past this stage or else it will burn and no one wants that! If you have a thermometer* the caramel should reach between 340°F and 350°F.
Once it is the right color, turn heat to low. Add in the butter and whisk together. Whisking helps the butter not separate, or if it does separate from the sugar it will help it incorporate. Adding the butter will cause the sugar to get really foamy and rise a bit. That’s good! Keep stirring until the butter is fully mixed in. (12 tbs unsalted butter)
Once the butter is mixed in, slowly pour in the heavy cream, whisking as you pour. The mixture will become slightly foamy again and that’s fine. As it mixes in completely it will smooth out. (1 cup heavy cream)
Stir in your salt if using (2 teaspoon salt)
Pour your salted caramel sauce into a glass container and allow it to cool. It will thicken up really nicely once fully cooled. If you need it to thicken fast, stick it in your freezer for 20-30 minutes.
Keep unused caramel sauce in your refrigerator up to 2 weeks!