Eggs are definitely an important part of a brownie recipe. Salt...you can most likely do without. Vanilla too, if you're really hard up. But eggs, well, eggs are very necessary. Otherwise you're left with something that is trying really hard to resemble brownies, but looks and tastes more like chocolate sand. And not very good chocolate sand either. So let this be a lesson to you all, if you're going to make brownies, and you're going to forget an ingredient, make sure it's not the eggs.