Yield: 2 cakes 2 tablespoons unsalted butter, softened 1/4 cup granulated sugar 1 large egg 1/2 teaspoon pure vanilla extract 1 tablespoon store-bought caramel sauce 2 tablespoons milk 6 tablespoons self-rising flour 1/2 teaspoon fleur de sel or other high-quality sea salt, divided 4 caramel candies, preferably salted 1. In a large mug, whisk together the butter and sugar with a fork. Stir in the egg, vanilla, caramel sauce and milk. Add the flour and 1/4 teaspoon of the fleur de sel. Beat the batter until smooth. 2. Divide the batter between two mugs. Top each mug with a pinch of the remaining fleur de sel. Microwave separately for 30 seconds each. 3. Top each mug with two caramel candies. Continue cooking 1 to 1 1/2 minutes more (each separately) until risen and firm.