You're going to be very surprised with the answer: Soy!
According to the United Soybean Board, when an egg is used as a leavening agent, as in muffins or sweet breads, you can substitute 1/4 cup of firm silken light tofu. (It probably would make sense to mash it before you blend it with the liquid ingredients in the recipe.) By using light tofu in place of the egg, you actually end up saving over 50 calories, over 200 milligrams of cholesterol, and 4.5 grams of fat. Silken tofu also works like a charm when you substitute it for sour cream in dips.
As for a substitution for the dairy milk, try soy milk. Look for the fortified version that has added calcium and the vitamins D and B12 to provide the important nutrients that would have been in the dairy milk.
You can substitute the soy milk equally for the dairy milk, so if the recipe calls for a cup of milk, use a cup of soy milk. When looking for a substitute for cheese, you can use mashed firm tofu in place of ricotta cheese, and soy-based flavored cheddar and Swiss cheeses, according to the United Soybean Board. Look for these in the refrigerated, health food section of your local supermarket. Substitute these in equal amounts as called for in the recipe. Here's a recipe for a yummy cinnamon dressing for fresh fruit or salads:
Cinnamon Honey Dressing
Updated: September 2005