This is the fourth in a series of 7 “Cake Batter” classes. We’ve been using the traditional “quatre quarts” pound cake recipe as a tool to understand the baking science of cake batter. This post will explore another ingredient in cake batter, eggs.

The same recipe made with varying amounts of eggs, yolks and whites.
In the 3rd class we looked at one of the cake structure-builders, flour. We learned that low protein, chlorinated cake flour produced a cake with a light and tender texture. Now it’s time to learn about the other structure-builder for cake batter, eggs.
To learn detailed information about the composition and science of eggs as an ingredient, please visit the Baking Ingredients – Eggs page. This class will focus specifically on eggs in pound cake batter.

Whipping the egg whites in the pound cake batter improved the texture of the cake.
The Function of Eggs in Cake Batter:
The most important job of eggs in a cake batter is to contribute structure in the form of proteins from both the yolk and the white. The protein coagulates as the cake bakes and, along with the starch from the flour, forms the cake crumb.
So what does all this mean for our pound cake recipe? It means we can alter the cake significantly by manipulating the number of eggs, yolks and whites in the batter.
What Egg yolks do in cake batter
The yolk contributes protein, but also some fat, flavor, and emulsifying lecithin. Because emulsifiers hold water and fat together, adding extra egg yolks to the batter enables the batter to hold extra liquid and, consequently, extra sugar. This helps create a moister and sweeter cake that will still bake up with a good structure rather than falling into a gooey mass.
What Egg whites do in cake batter
When separated from the yolks and whipped to a foam, egg whites can be used to leaven a cake. Whipping egg whites has the same effect as cooking whites- the proteins unfold, reattach and trap water. Since the whipped whites are already partially “cooked” they don’t contribute as strongly to the structure of the cake.
In my testing I found that a cake made with the same proportion of yolks and whites had a softer texture when the whites were whipped and folded into the batter.
If you find your cake recipe tends to be on the dry side, try swapping out some of the egg whites for extra yolks. If you find your cake has a poor structure or is gummy, you can add some extra whites. Want to lighten up the texture without adding more baking powder? Separate and whip the whites and fold them into the batter.
Testing different amounts of eggs in cake batter:
I wanted to see how changing the number of yolks and whites in our pound cake recipe would affect the final product. So I baked six cakes, changing the number of yolks and whites for each test.
I kept the other ingredients (butter, sugar, flour) to 8 oz each. Though I varied the number of yolks and whites, I kept the total weight of eggs for each test at 8 oz.
For the last two tests I separated the eggs, whipped the whites with 2 oz of the sugar, and folded them into the batter before baking.
There is no “right” answer as to which outcome is the best. It’s a matter of taste and what works for your purposes. But knowing how to use eggs to tweak your recipes is a valuable tool for every baker.
You can learn how I used this information to create a great White Cake Recipe from my Vanilla Butter Cake Recipe.
Our next “Cake Batter” class is all about the sweet stuff, sugar!
When we’re done experimenting with all the ingredients for this “cake batter” course, we’ll use all we’ve learned to create Pound Cake Perfection. In This comprehensive post about creating a great cake recipe you’ll find the perfected pound cake recipe, and lots of great information to help you adapt and create your own cake recipes.
If you love to learn about the basics of baking, you’ll love my new book: Easy Baking From Scratch: Quick Tutorials, Time-Saving Tips, Extraordinary Sweet and Savory Classics. The book contains over 100 recipes that have been well-tested and are presented in simple, clear language. It’s available now on Amazon.
janine
Thursday 4th of March 2021
Thank you for doing this research! very interesting! I understand that it is a matter of taste, yet I am curious as to which result you liked the best.
Eileen Gray
Thursday 4th of March 2021
If you look at my Pound Cake Perfection recipe you'll see the final result of all the testing.
Fareha
Thursday 11th of June 2020
Hey Eileen! Baking is obviously a skill one cannot acquire without much practice. This article helped so thankyou so much! However I have a question. I have a habit of collecting egg yolk since my dad is diabetic and he doesn't take it for breakfast. There are times when I run low on eggs when I am baking and that is when the collected egg yolk may come in handy; only if I knew how much to use. Could you please answer this for me? like if I have to use 3 eggs for a recipe, how much egg yolk should I use so that it doesn't make much difference? I'd be glad if you helped!
Eileen Gray
Thursday 11th of June 2020
Egg yolks and eggs whites will behave differently in the dough, as you learned in this article. If the eggs in a recipe don't do a lot of the structural work (like for cookies) then I would say you could use egg yolks at the same weight as the whole eggs. But for other recipes, like cakes, that rely on the egg whites to provide some of the structure I would be careful not to overdo it with the yolks as you could compromise the structure. A great way to use yolks is for making custards. I have an entire collection of recipes that use more yolks than whites.
BJ
Saturday 30th of March 2019
Hello, I AM STUDYING GCSE FOOD AND NUTRITION AND I WOULD LIKE TO KNOW WHAT THE EGG DOES IN A CAKE. PLEASE AND THANK YOU.
Eileen Gray
Saturday 30th of March 2019
Well, hopefully this article answers your questions. Let me know if you have any specific questions that aren't answered in the post.
Darden Pyron
Tuesday 26th of February 2019
I like fruit cake. I have some traditional recipes, but I always alter the ratios. Do you have a trustworthy recipe? Any classic ratio of fruits. Fruits to batter and such? Can I use your 4x4 cake recipe and then add the fruits? I've a half dozen more questions but I'll stop there! Thanks loads! Darden
Eileen
Wednesday 27th of February 2019
I have an aged fruitcake recipe that I've been using for 30 years. I love it. My recipe has about 2x the weight of fruit to cake. I also like this lighter "fruitcake" recipe made with Guinness.
Meg
Thursday 29th of November 2018
Hi, I've been trying to make a lemon cupcake but i wanted to base it off a plain one so i can learn about the chemistry of cupcakes better, I've altered some of the ingredients already but i was wondering if i could add an extra egg yolk and then the lemon and if so, how much juice could i add?
Eileen
Friday 30th of November 2018
An extra yolk would make the batter richer and it also helps emulsify the liquid in the batter. Generally, I like butter cakes with more yolks than whites for that reason. As far as lemon flavor, the zest of the lemon has the lemon oil, which gives more of the lemon flavor. So I would add finely grated lemon zest to the batter. You can also add a little lemon juice for acidity if you like. Replace some of the other liquid in your recipe with a tablespoon or so of the juice. It's hard to be very specific without knowing your recipe, but I always use lemon zest and lemon extract for lemon flavoring.