Egg yolk sizes changed over the years?

Hello @Dudie and welcome to Seasoned Advice. Regarding the size of egg yolks in certain size eggs, you may find this interesting. Here is the link to the page .

A change in the feed given to chickens has resulted in healthier eggs but the trend for buying larger eggs has led to there being less yolk to white. This is because of the preference for bigger eggs now compared with 30 years ago. The size of the yolk remains the same in a large egg as in a medium one, with larger eggs simply containing more white.

Looking at recipes for Norwegian cookies, I think that the recipe you are using is more widely known as Norwegian Butter Cookies. I found several using the same ingredients and they seem to be pretty consistent. The variations I found were mostly in preparation. E.g., one said to cream the butter and egg yolks together while another said to sieve the egg yolks.

The recipes I found for Norwegian Crowns used both cooked egg yolks and raw egg yolks (with the exception of one recipe that was nearly identical to all of the butter cookie recipes except that it called for vanilla).

So, in light of the information, I would offer these suggestions:

• Stay with the eggs you are using. If you think you need more, add more. If you think you need less, use less.
• You might give a look to other recipes and try a different prep method, e.g. creaming the egg yolks and butter together.
• As I saw in several recipes you can use a cookie press or use a drop method. If you use a ball or drop method you can use a fork to press in a criss-cross pattern. See pic below.

I have a speculation: there is nothing wrong with your yolk size, there is something wrong with your recipe.

Sometimes people transcribe good recipes and get a small detail wrong, because they don't know what it's there for. Then the recipe is much worse than it started out, but if the person who disseminates it is not too discriminating, it might become known enough to land in a cookbook.

I can imagine no good reason to mix hard boiled yolks with butter. On the other hand, there is a very good reason to do it if the eggs are not hard boiled. If you mix yolks and butter while gently heating over a waterbath, you get a hollandaise sauce, an emulsion which can be used as the base for very rich and fluffy batters. Also, this way the butter mixes with the rest of the ingredients perfectly even if you are not using an electric mixer.

Some recipes take the shortcut of not doing it over a waterbath, but to use a very soft cooked egg, where the yolk has just reached the proper temperature, but is still liquid. It still makes a decent emulsion, although not one a perfectionist would be happy with.

And then there are wrong applications of this technique which prescribe a hard boiled egg. I've tried before to see how it works, and found out that, even with a modern stick blender, it's impossible to make a good emulsion.

I may be wrong here, a dough can fail in many ways. But I can't think of another plausible reason for "creaming" egg yolk with butter. My suggestion is to try another batch, using an emulsification method, and then see if your dough works better.

Another point many people forget with cookie dough: using the correct temperatures is very important! Obviously, in this case you are starting with both eggs and butter at the correct temperature, but the other ingredients should be room temperature too. And if the recipe prescribes cooling periods, you should keep them, not try to skip resting or cooling steps. Else the consistency might be wrong for shaping, and they can bake wrong.