Um, OK, that may be a bit confusing... Yes, moussaka is actually a Greek dish. And there are a lot of variants, including different vegetables. But the moussaka that is generally accepted as a traditional Bulgarian dish is the potatoes and minced meat one, I think... Still, I find the idea of mushroom moussaka great :) and maybe I'll try it in the next days...

Most recipes for this dish go like this: you peel and cut the potatoes, you saute the other vegetables/ minced meat/ etc. You mix everything in a pan, put some salt and pepper (a bit of guessing and luck will help :)) The mixed yogurt and eggs plus the optional кашкавал are poured over (though you can also do that after the dish's been half-baked already). I usually bake it at 180-200C and it takes about 40-60 minutes... But the easiest way to find out if it's ready is to take a look and probably try it.