Before you begin, make sure you have everything ready to go - the cream and the butter next to the pan, ready to put in. If you don't work fast, the sweetener will burn. Heat butter on high heat in a heavy-bottomed 2-quart or 3-quart saucepan. As soon as it comes to a boil, watch for specks of brown (this is brown butter....SO GOOD on veggies!). Immediately add the sweetener and the cream to the pan. Whisk until caramel sauce is smooth. Let cool in the pan for a couple minutes, then pour into a glass mason jar and let sit to cool to room temperature. Store in the refrigerator for up to 2 weeks.
Place cocoa butter in a double boiler and heat on medium high until fully melted (or a microwave safe bowl and heat on high for one minute, check and heat for 30 seconds until melted). Melting cocoa butter takes longer than traditional fats.
Stir in natural sweetener.
Stir in extracts and salt.
Place melted chocolate into candy bar mold, enough to cover the bottom and sides, and cool in therefrigerator until white chocolate is solid, about an hour. Or the speedy method; you can place the molds in a freezer until they are set up, which will only take a couple of minutes versus an hour.
Once cool, fill the divots with caramel and set in freezer to set.
Once the caramel is set, remove from freezer and cover with additional melted chocolate.