I have a great meatloaf recipe but I don't have any eggs! Is there anything I can use to substitute for an egg?
In Sweden, breadcrumbs or porridge oats are sometimes used as an alternative to egg for binding köttbullar (meatballs). The crumbs or oats are mixed with boiling water and left for a while until you have a porridge-like consistency and then mixed into the ground meat.
Unfortunately I don't know the exact ratios of dry ingredient/water/ground meat since I generally use both egg and breadcrumbs. I would guess somewhere between 4 tablespoons and half a cup of dry ingredient for a pound of meat.
Most meatloaf recipes I googled have an egg in them. It's probably there as a binder, to hold the loaf together, rather than flavour - similar to how many people add a little egg to a hamburger mix to help the hamburgers hold together. However, just like a hamburger, in a meatloaf you could get away without using the egg, depending on how dry vs. meaty the recipe is.
Mix you loaf as normal but when finished mixing, give it a kneading like your would normally knead bread. Then put it in your refrigerator for a hour or two to chill it. When you chill it, the proteins in the meat (which have been stretched by kneading) will coil up and lock together. Now cook the loaf normally. When you cut the meatloaf you will find it will hold itself together well enough without the egg.
There is this article in the NYT about using ground flax seed as an egg substitute.
I have used this with good results in cookie recipes and would expect similar results with meatloaf.
However not having eggs but having ground flax seed seems a bit of a stretch. In that case, I would just make meatloaf without the eggs, I don't think there would be that much of a problem.
My normal recipe calls for an egg and the 1 minute quaker oats in place of bread crumbs but I was in a pinch today with no eggs. Instead of using the oats dry in the meat mixture, I cooked them as if making oatmeal and kept it on the thick side. I also used a 1/2c shredded mozzarella cheese and found it binded nicely.