If the cake recipe says 3 large eggs but I have small/medium (cuz organic) eggs ... Do I stick to 3 or add another?

The average large egg is equal to 1.66 ounces. That times 3 = 4.98, call it 5 ounces. Use a liquid measuring cup, and add your medium eggs until you reach 5 ounces. Err on the high side rather than the low.

I would definitely add an extra egg. A bit more egg will give you extra lift and you might have to add a few minutes to the cooking time, but not enough will result in a dry, crumbly cake.

I would throw in an extra egg. Small is a lot smaller than Large or Extra Large eggs.

Red velvet! Thank you!

Red velvet! Thank you!

Red velvet! Thank you!

I would go with 3 whole and one extra yolk. What cake are you making?