why isn't it "מכינים" or "אופים"? It would technically be grammatically incorrect, both in English and in Hebrew.
I know that, but considering the fact that there is a verb (אופים/ofim/baking) that means to make a cake, muffins, etc., why would you use עושים/osim/making?
Maybe it is a cold cheesecake that goes in the freezer and doesn't get baked?
All of these verbs can describe the making of a cake. However, in this exercise you were asked to translate עושים, and the translation of the word עושים is making :)
It's not. It's a general statement.
Like "how does one make a big cake".
There are different ways of saying it.
I don't think "they" is used in English for the same purpose.
French uses "on" which is closer to they. Or we, perhaps.
Because your sentence makes big an adverb. In the original it's an adjective.
Alternatively, you're making it a noun of its own (hours do you make a cake so that it's a big cake).
The Hebrew sentence means only "big cake"
Let's test this out:
How can scientists make a person young? How do ovens make a dish hot? How does you not getting this concept make someone like me frustrated?
All of those adjectives in sentences with a similar structure are not suddenly adverbs, therefore "big" in "how does he make a cake big?" is not an adverb.