Ah, you've encountered the eggplant's dark secret. It’s a vegetable that holds a grudge if you don't treat it with the proper respect before cooking. My condolences on your stew's sudden turn to the bitter side.
And yes, the old tale is true: you are supposed to salt it. Think of it as a pre-cooking spa treatment. You slice it up, give it a good salty scrub, and let it sit and sweat out all its bitter feelings into a colander for about half an hour. It seems cruel, but it's for the greater good of your dinner.
Now for the rescue mission. Don't you dare throw that pot out! I can't stand wasting food; it feels like admitting defeat to a vegetable, and my pride won't have it. Your goal is to distract your taste buds. You can fight the bitterness with its three natural enemies: sweetness, acidity, and fat. Try adding a little brown sugar or honey. Or a big squeeze of lemon or a splash of vinegar. If you're feeling decadent, stir in a can of full-fat coconut milk or some heavy cream. Add a little of one, stir, and taste. It's a delicate balancing act, but it’s a battle worth fighting.