I've been doing something similar (maths in an Anki deck), and I haven't found a good way of doing so. My current method is just asking "Prove x" or "Outline a proof of x", with the proof wholesale in the answer, and then I run through the proof in my head calling it "Good" if I get all the major steps mostly correct. Some of my cards end up being quite long.
I have found that being explicit with asking for examples vs definitions is helpful: i.e. ask "What's the definition of a simple ring?" rather than "What's a simple ring?".
"def(simple ring)" is more efficient than "What's the definition of a simple ring?"
If it's worth saying, but not worth its own post, even in Discussion, it goes here.