[cbhl]

Assuming that the boxes are 13.25oz/18.25oz, looks like an updated recipe could be:

- 2 boxes cake mix

- 3 eggs (rounding up from ~2.9 eggs)

- 1/2 cup neutral oil (rounding up from ~0.48c)

YMMV

[foofoo12]

I think you need 371 boxes of cake mix to skip rounding errors. Granny wants consistency.

[cheschire]

The factory must grow.

[twodave]

Ostensibly not since she didn’t bother changing the recipe when the box shrank to ~15oz.