I have one recipe that calls for several egg whites, and no egg yolks that I plan to make soon. I have other recipes that call for more yolks than whites (which I am not planning on using 'soon')... How long will egg yolks 'keep' in the fridge? (alternatively/additionally) Can yolks be frozen (for instance, in an ice cube tray) an preserved?
Egg yolks, optionally covered with water, and in a well sealed container should hold for about 2-3 days in refrigerator.
You may also freeze them, but they require treatment with sugar or salt to prevent the proteins from turning them rubbery, at ratio of about (per the Egg Board):
per 1/4 cup of egg yolks (about 4 yolks).
Of course, you then have to adjust whatever recipe you use them upon thawing to account for the sugar or salt already mixed into the yolks.
See also: Still Tasty