What happens when you add more eggs to a standard cake recipes'?

This really depends on HOW you add the extra eggs.





If you add only whites and beat them first the cake will be taller and have a lighter crumb, like angel food cake.





If you add only yolks, the the color will deepen and the cake will be more dense.





If you add whole eggs the overall change will generally be a more dense cake because most people won't separate to increase air volume in the batter. The caution is exceeding what the batter can hold as eggs. Too much egg and the cake becomes tough and eggy (how is that for a descriptor!)


but also seems to look a bit stringy.





I have chickens and sometimes am faced with wanting to use


up one more egg vs discarding the egg since I know I won't be baking for a while. I only give away eggs that are less than 48 hours old. I use them for my own baking up to 3 weeks old. Most often I don't have 3 week old eggs in my refrigerator though!





If I had a cake recipe that required 2 eggs I would add a third and not worry if the cake were a typical yellow cake. If my cake recipe required 3 eggs I would probably not add the 4th unless the eggs were smaller than usual.





If the cake were higher in fat (like a flourless chocolate cake) I also would not add the extra egg.





These comments are in relation to a single 9 x 13 cake pan type cake or single boxed cake mix. I would think it is obvious that making 5 full sheet pans of cake would not have the same impact by an single additional egg, vs the 1/4 sheet that is typical of the home baker.What happens when you add more eggs to a standard cake recipes'?
The mass will turn too moisty and like bubble gum..What happens when you add more eggs to a standard cake recipes'?
It may be a little more moist, but if you cook it well then the whites will cook too. If they were whipped, it might be a lighter cake, with more bubbles. If it was only 1 or 2 extra, i doubt you will notice any difference to be honest.
you may get a denser cake from the extra fat but it'll still be good.