What changes, and what does not
What egg actually does in a chocolate chip cookie
Held against all six outcomes we can measure, not just the
one that would make the best headline.
What egg does
5 bakes
Expect a looser middle, and plan for it
More egg gives a firmer, more finished centre. Take it out and the middle stays softer for longer.
This is the one place egg showed up as a real lever across the whole corpus, and it is not chew or spread. Egg protein sets as the cookie heats, so more of it means the centre stops changing sooner. That is what “underdone in the middle” and “fully set” physically are. Without egg, bake to the edges and let the tray finish the centre.
On five other outcomes, the egg-free cookies sit right alongside the
rest. Egg is one of the ingredients recipes vary most, so there was
plenty of room for a difference to show. None appeared against chew,
spread, edge crispness, browning or perceived sweetness. That is not the
same as saying egg does nothing to them: it means any effect is smaller
than the spread across this corpus, which is the honest shape of it and
the reason we would rather write it out than flatten it into a slogan.
- How dark it bakes: no effect we could detect.
- How chewy it eats: no effect we could detect.
- How crisp the edge gets: no effect we could detect.
- How far it spreads: no effect we could detect.
- How sweet it tastes: no effect we could detect.
- Tang: no effect we could detect.
Reviewers made 3 distinct claims about egg or yolk specifically, with 10 mentions backing them and none against. None of that testimony pushes back on what the corpus shows. If
chew is what you're protecting,
the tips that actually move it are brown
sugar and total sugar, not egg.