When I think of gyros I think of lamb or kid roasting on a spit, but several online recipes point out that a reasonable facsimile can be made with ground beef in a rectangular pan under the broiler. Since my freezer contained an eye of round roast that I could not imagine getting tender any other way, I decided to try it in my NuWave countertop oven.
I ground cubes of the fresh round in a Ninja, added seasonings, and then kneaded the whole thing together with a handful of crumbled Sourdough bread. One recipe said that kneading was an important step. After packing it into a mold spread with bacon grease, I baked it for 15 minutes and then left it in my NuWave oven while I went shopping. Upon my return I sliced the wonderfully brown meat thin and tried some. I like it and now know what to do with a tough cut of meat.