For these cookies, I made 1/3 recipe this time. How, you might wonder, would I adjust the 1 egg and 1 egg white by 1/3. I first calculated the 1/3 amount of egg and egg white needed in grams. Then I separated the egg yolk from the egg whites. Then I weighed them separately. The egg yolk weight 16 grams so it's normal size, so I split it into 1/3 (5 grams). I add the amount of egg whites needed for 1/3 of egg weighted. Are you still with me? And lastly I added then 1/3 additional egg whites.
It dawned on me recently (thanks Rose), that I should probably mention any high altitude adjustment that I make on recipes. I think all of the Alpha Bakers are at sea level so this is probably not very interesting. But perhaps it can be useful for others reading this blog if they happen to be at high altitude. Denver is at 5,000 feet above sea level so adjustments needs to be made for cooking and baking.
I usually adjust two things: leavening agents and liquid. Decreasing leaving agents is because at high altitude baked goods rise more quickly. The second adjustment is increasing liquids. I always thought that increasing liquids is because it's so dry here but that is not the only reason. At higher altitude, evaporation happens faster so add that to the dryness baked good taste less good. Some folks adjust the dry ingredients: increasing flour, reducing sugar, etc. I feel that increasing flour is counter-intuitive to adding liquids to prevent dryness so I never really bother with that. As for sugar, Rose's recipes is not too sweet so that's not needed, in my opinion. It is not as complicated as it might have sounded. Trust me on this - I almost failed high school chemistry.
For this gingersnaps I adjusted the baking powder and baking soda by about 20%. I didn't measure very accurately since it's impossible to split 1 teaspoon baking soda into 1/3 and then reduce 20%. Let's just say I measure 1/3 of it and then take a bit off.
I waited until everything is being mixed in the mixer, the batter almost come together with the stated amount of eggs. There's still a few stray crumbs left and the batter feels a tad dry to the touch, so that's when I added 1 tablespoon of egg whites to it and mix it by hand. I avoid using the mixer at this step since it is harder to mix a dough that's already come together with additional liquid - at least that's how I think of it in my head haha.
1/3 recipe yield 10 cookies, all exactly 27 grams.