Ooh, there's alot. The first one that comes to mind is for strider stew. You get that quest in Auberdine.
Edit: Use the database here to find everything you need. Go to the "Items" category to the left and click on 'Lookup'. Type the word 'recipe' into the search field and search. It will list all of the recipes (including non cooking recipes). You can go through each recipe and it will explain whether the recipes are bought, quest rewards, or both.
I've also noticed that some recipes yield dishes that sell more to vendors than the combination of the ingredients combined. For example, the Herb Baked Egg; a starting recipe when you obtain the cooking skill. I used the eggs that drop from moonkin kills in Auberdine. Once cooked, they sold to vendors for a price much better than the value of the vendored eggs and the price of the mild spices.
Edited, Sun Mar 6 13:17:23 2005 by Spittle
Some people are like Slinkies. They aren't really good for anything, but you can't help but smile when you see one tumble down the stairs.