Add chia seeds to a small dish and top with water. Stir and let rest for 5 minute to thicken. It should be gel-like and thick.
It's not an exact 1:1 substitution in every recipe because it doesn't bind and stiffen during baking quite like an egg does. But, similar to a flax egg, it works well in pancakes, quick breads, muffins, cookies, and many other baked recipes. Chia seeds also make a delicious chia pudding, like this Chocolate Chia Pudding and PB&J Chia Pudding!
*Nutrition information is a rough estimate. *This is not my original recipe, but one I discovered on many vegan baking blogs and have since adapted for my own use.