No. Because vostru need the article. When a possesive pronom stays near a noun, you must not use the article
I only know sau = or. Please note that the diacritical signs really matter in Romanian; sau is different from său.
Microsoft's long-time refusal to support Romanian characters in Windows has made some Romanians a bit careless about diacriticals…
Is this supposed to translate to "Is this our cake or yours?"? Sound funny this way
It just means what the proposed translation (our cake or yours) says. What you add mentally lies in the ear of the listener: “Is this…, ” “Shall we have a piece of…,” “Which one do you prefer: …”
The structure is identical to “your place or mine,” which does not sound funny to me. Or do you mean “The sound is funny this way?”
Then the question would sound like this : "Tortul este al nostru sau al vostru?".