Phrase "let alone a cake"

[Nessie]

Hi, please have a look at this:

She came into the chook yard, poked in the nest, then looked at the chickens and lectured them severely: "Forty of you, and only fifteen eggs! Not enough for breakfast, let alone a cake"

=> I don't understand what "let alone a cake" here means. Does it mean that those 15 eggs are not enough even for just a cake, not to mention the whole breakfast?

Thank you very much.
Nessie.
_________________
... something we never have again, I know... I guess I really really know..

Sorry seems to be the hardest word...

[Benjamin]

Hi nessie,

this is an expression of "not enough"
it is used to reinforce how little or few are present of what is needed to achieve or get something
OR
it underlines how useless the amount you currently have is

the second half of the expression (the part that follows "let alone") should always be more than the first part

e.g. she needs 40 eggs for a cake, but needs 20 for breakfast. the expression is stating that the amount is so small there aren't enough to even make breakfast (the opposite of what you said)

another example might be:

i've only got £100. that's not enough to get me to Germany, let alone Thailand.

what do you think is meant there?

[Nessie]

Thanks a lot for your help, Benjamin

As for this sentence:
I've only got £100. that's not enough to get me to Germany, let alone Thailand.

=> I think it means 100 pounds is not even enough to get to Germany, so certainly it's not enough to get to Thailand, which must cost much more. Am I right?

Many thanks once more
_________________
... something we never have again, I know... I guess I really really know..

Sorry seems to be the hardest word...

[Benjamin]

spot on

the speaker is hoping to go to thailand, but the amount he has is so small that it won't even get him half way, and he is just highlighting this
the use of "thailand" in that sentence cannot be changed but many other countries or places could have been used instead of Germany (as long as they were closer than Thailand)