Begin by preheating the oven to 350 degrees Fahrenheit. Proceed to grease a 9x13-inch baking pan with a suitable non-stick cooking spray. Once prepared, set it aside.

In a large mixing bowl, combine the carrot cake mix, instant vanilla pudding mix, eggs, whole milk, sour cream, vegetable oil, and chopped pecans (if desired). Mix the ingredients thoroughly until a consistent batter is achieved. Transfer the batter to the previously prepared baking pan and smooth the surface for even baking.

Place the baking pan in the preheated oven and bake the mixture for approximately 40 to 45 minutes or until a toothpick inserted into the center of the cake comes out clean.

After baking, remove the cake from the oven and allow it to cool to room temperature within the pan. Once adequately cooled, use a skewer or a similar instrument to create uniformly spaced holes throughout the entirety of the cake's surface.

Gradually pour the sweetened condensed milk over the cake, ensuring it is evenly distributed and adequately seeps into the holes. Leave the cake to absorb the milk for a minimum of 1 hour. If feasible, allowing it to sit overnight is recommended for optimal absorption.

In a separate mixing bowl, combine the heavy cream, instant cheesecake pudding mix, and powdered sugar. Whisk these ingredients together until a light and airy frosting consistency is achieved. Once done, apply the frosting uniformly over the surface of the cake.

Finalize the preparation by drizzling the salted caramel sauce over the frosted cake and garnishing with the finely chopped pecans. Slice the cake into desired portions and serve. Store any remaining portions in the refrigerator, securely covered, for up to 2 days.