My go to question for interviewing candidates is "What trends do you see in web development now or you see being important in the next few years?". There's no right answer there, I'm just looking for something relevant that shows they've got some knowledge of the field outside of being able to bash out code to order. For juniors I don't really expect much while seniors should at least be able to talk a bit about a couple of things, but having interviewed prospective head of development candidates I was amazed that two out of four just tanked on the question, one just couldn't answer at all.

Candidates who know there are things they don't know about I don't mind, but candidates who are unaware of these things at all are typically uninterested in broadening their knowledge, and not someone I'd like on my team.

Can you outline what you might expect in an essay exam for a software engineer position?

Would it take the form of a standard interview question:

"Write a few paragraphs on what happens when you press a key on the keyboard"

Or would it use the medium to ask a question less appropriate in an oral interview process?

Genuinely curious what you envision with this format.

The goal is to assess a candidate’s ability to communicate technical matters quickly with structure, organization, and planning. Secondary considerations include the ability to follow simple instructions, command of written language, and accurate descriptions of technical subjects.