Double Yolk Eggs

One of our kids brought me a tray of twenty double yolk eggs.  Double yolk eggs are seldom found in store bought eggs because they are removed during packing.  As a kid, I was delighted to find a double yolk egg.  My Mom bought eggs from the local egg lady who actually delivered them to her door.  Years later I had an egg lady who also delivered eggs to our door and since I still buy eggs from a local organic farmer, I come across double yolk eggs more that some may.

My gosh, it is not often I get to bring my discipline into the conversation on this blog because it is focused on cooking.  For those who do not know, my discipline is medical genetics.  First, many think there is a difference in flavour between white and brown eggs to the point some stores actually charge more for brown eggs.  The egg colour is determined by the chicken breed, with brown chickens laying brown eggs.

Double yolk eggs (right) are almost double the size of extra large eggs (left).  A double yolk egg is essentially a reproduction error.  Eggs are produced via a process called meiosis, a type of cell division that produces gametes with half the number of chromosomes (n or haploid) of the parental cell (2n or diploid).  One parental cell (2n) forms four gametes (n).  Meiosis is a two step process consisting of DNA replication and reduction division (Meiosis I)  followed by the second stage of equational division (Meiosis II).    The eggs we eat are unfertilized (haploid).  What happens to form a double yolk eggs is the failure of the chromosomes to separate at Meiosis I or the sister chromatids to separate at Meiosis II.  Abnormal separation of chromosomes during meiosis is termed nondisjunction.  Now you know how double yolk eggs happen.

Double egg yolks are actually quite frugal if you can find an entire dozen or more.   Store bought extra large eggs are currently $3.47 or  29¢ each.  Double yolk eggs are $6 for 20 or 30¢ each but because they are almost double the size of extra large eggs and have two yolks it works out to almost 15¢ per egg (yolk).  Using double eggs reduces the number of eggs you have to crack (aka saves time) while giving the same results as you would get from using two extra large eggs.

Double yolk eggs are particularly frugal when making homemade pastas using only yolks as well as any other recipe using only egg yolks.  They are great for making omelets and scrambled eggs.  As pictured, you only have to crack one for fried eggs.  Don't they look lovely?