Fixing cooking mistakes really isn't as hard as it sounds. It happens to all of us, at one time or another, and most have a relatively easy fix. Even the best cooks have cooking disasters that need help so here are the most common ones with a guide to help you out of the fire and back in the frying pan! I'll keep adding to the "fixing cooking mistakes" page as new fixes come up.
Okay, so you were distracted and added salt twice, or you read the recipe wrong, but it happened. The food is so salty it is barely edible. There are two ways that I know of to fix this problem. The first is peel a potato, cutting it into large chunks that you can later fish out--or leave in if the dish happens to be a stew or soup where potato works. Simmer the dish for 15-20 minutes and taste.
If it works, great! If not, on to the second method (of if it is really, really salty, just go for the second method to start with). You can neutralize the saltiness by adding sugar and cider vinegar. Use 1 teaspoon of each and taste. Keep adding a teaspoon of each until you have alleviated the saltiness. Also, you may want to have someone else taste test for you as your taste buds might be a little numb from the original salty flavor.
This happens to me all the time when I make chili. I like things hot and while it tastes great to me, no one else in my family can eat it. The first thing I do is to add chocolate. The sugar works to neutralize some of the heat. It won't hurt the flavor of your chili, and completely disappears. If the chocolate isn't enough, I add sour cream; a quarter of a cup at a time. It makes the chili thicker, completely dissolves, and also dilutes the spice. The sour cream, plain yogurt or milk will also work for many cream sauces, as well.
Lime or Lemon juice is another option to neutralize the heat because of the acidity. It adds great flavor to a lot of your Mexican dishes like salsa.