Heat sugar and water in a large skillet or wide saucepan with a lid, over medium heat. Swirl the pan very gently, just enough to evenly cover and moisten sugar with the water. Cover pan and cook for 3 minutes. 

Remove lid, and allow sugar to boil for 5 minutes, or until it’s a deep amber color. Once a candy thermometer registers 350°F, carefully and slowly add butter and cream, as adding these ingredients will cause the caramel to sputter and steam. Stir until butter is melted and cream is incorporated.

Add vanilla extract and a pinch of sea salt. Cool slightly before moving sauce to a heatproof container. Store in the refrigerator, up to 2 weeks. Serve sauce with apple slices, pears, pound cake, cookies, etc.