Gather your ingredients and equipment, including a large mixing bowl and a slow cooker.

Combine the Devil's Food Cake mix, 3 large eggs, 1 cup of water, and ½ cup of melted unsalted butter in a mixing bowl and blend until smooth.

Pour the batter evenly into the slow cooker, ensuring it is coated with non-stick spray or butter.

In a separate bowl, mix sweetened condensed milk, ½ cup caramel topping, and 3 chopped Heath bars. Drizzle over the batter in the slow cooker.

Cover the slow cooker and set it to cook on low for 4 hours, or until the center is set.

Let the cake cool for about 30 minutes before serving and enhance with Cool Whip and additional caramel or chocolate sauce if desired.