As a once very avid baker, I've had my fair share of moments Google-ing "egg-less cookie recipes" or "cake recipes that don't require butter", just so I didn't have to run to the store for one ingredient. Through these moments of desperation and laziness, I have racked up a couple simple baking ingredient substitutions for common ingredients that you probably already have in the kitchen.
1. Avocado instead of butter
Using avocado in your baked goods might sound like an odd thing to do, but think about the faint taste of avocado, you'll barely notice it in the mix of all that sugary goodness. Butter is often used to soften the texture of foods, as well as adding in a bit of fat for substance. Well, avocado basically has the same consistency as butter and contains quite a bit of fat too.
Substitute the ingredients with a 1:1 ratio, so if the recipe calls for 1 cup of butter, use 1 cup of mashed avocado instead.
2. Chia seeds and water instead of an egg
Also commonly known as a "chia egg," this substitution is quite popular in many vegan recipes, as using eggs aren't even an option in those cases. Something about the mixture of chia seeds and water creates a consistency similar to that of an egg, which ultimately is a binding agent for all the ingredients.
For the replacement of one egg, mix one tablespoon of chia seeds in three tablespoons of water and let the mixture sit for 10 minutes.
3. Applesauce instead of sugar
Applesauce is already naturally sweetened, so even if you only have unsweetened applesauce sitting around the house, it'll still work just fine. For people looking to cut down on refined sugars, this is a great tip to start using in the kitchen. The natural sweetness, the subtle apple flavor, and the added moisture will definitely not hinder the taste of your treats.
For each cup of sugar that the recipe calls for, use 1/2 cup of applesauce.
4. Banana instead of an egg
This one is another very common substitutions that many vegans use when baking. It does just as good of a job binding all the ingredients together and as an added bonus will give whatever you're making a subtle banana flavor.
I recently started making this vegan pancake recipe that uses banana instead of eggs and it makes them taste like delicious banana bread pancakes.
Use 1/2 a mashed banana (about 1/2 cup) per one egg that the recipe calls for.
5. Greek yogurt instead of sour cream
Even though sour cream isn't too common of an ingredient, there is still a fair share of recipes (like this one) that call for it. In fact, this is another much better option for those who are a little more health-conscious. The sourness of greek yogurt adequately mimics the taste of sour cream, and not to mention the textures are pretty much identical too.
Use equal parts of greek yogurt to however much sour cream the recipe calls for.
Hopefully, this will save you from either having to forgo that baking adventure you were excited to go on or having to run all the way out to a store just for one missing ingredient. And if you haven't noticed, a lot of the substitutions are also healthier alternatives you might want to try out anyways.