Making Greek Steak Gyros is a straightforward process. Follow these simple steps:

1. Prepare the Marinade: In a bowl, mix olive oil, red wine vinegar, minced garlic, oregano, ground cumin, salt, and pepper.
2. Marinate the Steak: Add the flank steak to the marinade, coating it well. Cover and refrigerate for at least 30 minutes or up to 1 hour for enhanced flavor.
3. Make Tzatziki Sauce: In a separate bowl, combine Greek yogurt, grated cucumber, minced garlic, olive oil, lemon juice, salt, and pepper. Mix well and refrigerate until ready to serve.
4. Preheat the Grill: Heat your grill or skillet to medium-high heat.
5. Cook the Steak: Remove the steak from the marinade and grill for 5-7 minutes per side, or until it reaches your desired doneness. Aim for medium-rare for the best flavor.
6. Rest the Steak: After cooking, let the steak rest for about 5 minutes before slicing it thinly against the grain.
7. Prepare the Pita: Warm the pita bread on the grill or in a toaster for a few seconds until soft and pliable.
8. Assemble the Gyros: Place the sliced steak onto the warm pita, followed by diced cucumber, diced tomatoes, sliced red onion, and crumbled feta cheese.
9. Top with Tzatziki: Generously drizzle the homemade tzatziki sauce over the fillings.
10. Garnish: Add fresh parsley or dill as an optional garnish for added flavor.