Using egg whites for extra hold in the cake batter?

Hi there! I just talked with Nea about your question and she responds:

"Usually, 2 egg whites in weight are the same as 1 whole egg, so you may be able to substitute a few egg whites for one egg. However, you'll lose a little fat from the missing egg yolk. You could also try using 5 whole eggs and experiment using an few egg whites (like you mentioned). If it's a noticeable height difference though in the cups (three cup method) with the eggs, flour and sugar, you may want to up the sugar and flour, too. Hope that helps!"

Ampersandwich -

I haven't made this recipe yet, but share your worries about the volumes and weights.

Also consider the eggs - five large eggs makes between 1.17 and 1.25 cups liquid, depending on your factor translating them to imperial measure.

For a comparison of measurements, maybe have a look at this recipe for the Swedish Midsummer Cake, adapted from Strawberry and Cream cake, called “Gräddtårta med Jordgubbar.”

https://www.lavenderandlovage.com/2020/06/swedish-midsummer-cake-with-berries-and-cream.html