In a medium saucepan, combine sugar and water over medium heat. Stir gently to dissolve the sugar, then stop stirring and let it boil for about 4-5 minutes. Keep an eye on the color as it transforms to a deep amber. Once it reaches that beautiful hue, remove it from the heat; add butter and salt, whisking until the mixture is smooth. Gradually mix in heavy cream, stirring carefully, and let it cool slightly.

In a separate bowl, whisk the egg yolks until they are light and frothy. Slowly pour the warm caramel mixture into the egg yolks, whisking continuously to prevent cooking the eggs. Once combined, return this mixture to the saucepan and cook over medium heat for about 3-5 minutes, stirring constantly until it thickens slightly and coats the back of a spoon.

After thickening, remove the saucepan from heat and stir in the vanilla extract. Allow the caramel custard to cool to room temperature. Once cooled, cover and refrigerate for at least 1 hour to let the flavors meld and the mixture firm up.

In a mixing bowl, pour in the heavy cream, powdered sugar, and a pinch of salt. Using an electric mixer, beat the cream on medium-high speed until stiff peaks form, which should take about 3-5 minutes. The whipped cream should be fluffy and hold its shape—perfect for folding into the mousse.

Once the caramel mixture is chilled, gently fold the whipped cream into the cooled caramel custard with a spatula until it is well combined and smooth. Be careful not to deflate the whipped cream, as you want the Salted Caramel Mousse to remain light and airy.

Spoon the mousse into your favorite serving dishes and refrigerate for at least 2 hours to set properly. When ready to serve, enjoy it chilled, optionally topped with extra whipped cream, a drizzle of caramel sauce, or a sprinkle of sea salt to enhance the luxurious flavor.