In a medium saucepan over low heat, combine sweetened condensed milk, caramel sauce, unsalted butter, and vanilla extract. Stir gently for about 5 minutes until the mixture is smooth and creamy, being careful not to let it boil.

Remove the saucepan from heat and stir in the semi-sweet chocolate chips. Keep stirring for an additional 2-3 minutes until the chocolate is completely melted and fully incorporated, resulting in a thickened fudge mixture.

Line an 8x8 inch square baking pan with parchment paper for easy removal. Pour the rich fudge mixture into the prepared pan, smoothing the top with a spatula. Refrigerate for 1 to 2 hours or until the fudge is firm to the touch.

Once the fudge is firm, remove it from the refrigerator and let it sit at room temperature for about 5 minutes. Scoop out small portions of the fudge, roughly the size of a tablespoon, and roll them into smooth balls using your hands.

While the fudge balls chill, melt the couverture chocolate in a microwave-safe bowl or a double boiler until completely melted and smooth. Let the melted chocolate cool slightly.

Remove the truffle balls from the fridge. Dip each one into the melted chocolate, making sure they are completely coated, then lift them out using a fork. Allow excess chocolate to drip off before placing each coated truffle back on the parchment paper.

While the chocolate is still warm, sprinkle each truffle with flaky sea salt and drizzle with optional caramel sauce for added flair.

Allow the coated truffles to sit at room temperature until the chocolate has completely set, about 30-60 minutes, or refrigerate for 15 minutes to speed up the process.