Eating healthier doesn't have to be a bore. By making simple substitutions in your baking recipes, you can bump up the nutrition and lower the cholesterol and fat content without sacrificing any flavor at all. This is what they call "having your cake and eating it too," right?
Applesauce for butter or oil
It's true! Unsweetened applesauce can be used to replace part or all of the butter in a recipe. It can be swapped in equal quantities, so if a recipe calls for two cups of butter, you could replace as much of it as you'd like with applesauce. Anything from a small amount — say 1/4 cup — to the entire amount is fair game.
Using all applesauce in a cake or bread will give it a lot of moisture, but also a lot of density, so keep that in mind when choosing how much of the butter to replace.
Applesauce for eggs
Unsweetened applesauce can also be used as an egg substitute. Use 1/4 cup of applesauce for 1 egg.
Applesauce for sugar
You can swap unsweetened applesauce for sugar in a 1:1 ratio in recipes, but you'll also need to reduce the amount of liquid in the recipe. Usually reducing the liquid (milk, water, etc) by 1/4 cup will do the trick. If there's no added liquid, then there's no need to adjust.
Avocado for butter
You can swap equal amounts of mashed avocado for softened butter in baking recipes, and it can even be used to make buttercream. Avocado will definitely impart a flavor, along with its natural sweetness, so choose your pairings accordingly. Chocolate works beautifully with the sweetness of avocado.
Bananas for eggs
Mashed bananas (extra ripe is best) can be used for eggs in certain recipes, using 1/4 cup banana for 1 egg. Bananas are a great binder but won't provide lift, so they're better for baked goods that don't require much lift or that already contain leavening. Bananas do have a distinct flavor, so choose recipes where that flavor is welcome, like oatmeal cookies, bread pudding and quick breads.
Greek yogurt for sour cream
In general, you can trade equal amounts of plain Greek yogurt for sour cream without really changing the result. Greek yogurt can also be used to make cake icing — just replace part (or even all!) of the butter.
Vegan "butter" for regular butter
Butter substitutes like Earth Balance bring the benefits of butter in baking, with a healthier twist. Be sure to use butter substitutes that are specifically labeled as baking-appropriate, and use in equal quantities to butter.
Egg whites for whole eggs
Substitute 2 egg whites for one whole egg if you're looking to avoid yolks. This is also an easy way to use extra egg whites if you happen to have any on hand. It works great for cookie or quick bread recipes.
Milk for cream
This is an easy one, but it's totally effective in making baked goods healthier. In most baked good recipes, you can substitute milk (or reduced fat milk) for cream. Just don't do this in recipes like whipped cream, because you need the cream's fat for structure. In a cake batter, though, you could easily substitute cream with milk.
Flax meal for eggs
That's right — these seeds aren’t just a heart-healthy topping for your oatmeal. They can be used for vegan baking with one tablespoon of ground flax seeds + three tablespoons of water to replace 1 egg.
Marshallow fluff for buttercream
Granted, this isn't health food. But you can lighten up your buttercream by mixing it with an equal amount of marshmallow fluff and mixing until you've reached a spreadable consistency. The sweet fluff is full of flavor, but low in fat, so it'll help lighten up your cake.
Oil for butter
In plenty of recipes, oil can be substituted for butter in equal quantities. Olive oil in particular can give baked goods a unique taste and texture, and it's rich in omega 3 fatty acids. It will affect the texture of your baked goods though; it's different, but not in a bad way.
Prune purée for butter
Just like applesauce, prune purée can be substituted in equal parts for butter. Replace part or all of the butter in a recipe with the prunes. For an extra easy shortcut, buy the pre-pureed stuff (aka baby food).
A pastry chef once told me that in general, you can cut down 1/4 cup of sugar in just about any cake or cookie recipes without huge consequences. I have found this to be true in my experience; so you can take that tip or leave it.
Another variation of the same trick is to cut down on the sugar by 2 tablespoons per every cup of sugar, and to add an extra 1/2 teaspoon of vanilla.