I have a great Mrs Beetons recipe for Almond Icing. However, as it's a very old recipe and calls for the whites of 4 eggs what size egg should I use. As eggs on the whole have been getting smaller over the years. Yes I can see that egg yolk sizes have been discussed on the site, but not this particular problem that I have.
ALMOND ICING FOR CAKES.
- INGREDIENTS – To every lb. of finely-pounded loaf sugar allow 1 lb. of sweet almonds, the whites of 4 eggs, a little rose-water.
Mode.—Blanch the almonds, and pound them (a few at a time) in a mortar to a paste, adding a little rose-water to facilitate the operation. Whisk the whites of the eggs to a strong froth; mix them with the pounded almonds, stir in the sugar, and beat altogether. When the cake is sufficiently baked, lay on the almond icing, and put it into the oven to dry. Before laying this preparation on the cake, great care must be taken that it is nice and smooth, which is easily accomplished by well beating the mixture.
Best Answer
There is no absolute conversion as egg sizes were not standardized back then. For the USA, not England, the food timeline http://www.foodtimeline.org/foodeggs.html under the section "Egg sizes the USA" (about 1/10th of the way down) starts with (bolding added):
Recreating old recipes with modern products always poses special challenges. When eggs are on the shopping list, think small or medium.
The section continues with various extracts describing approximate weights and other commentary.
From the above, I would go with Dorothy's comment and use medium, starting with two or three and adjust for consistency. Don't forget to weigh what you use so that you can repeat your success with any eggs.