- 3 pounds sirloin strip, fat trimmed and cut into twenty-four 1- to 1½-inch cubes
- ¼ cup extra virgin olive oil
- 1 tablespoon dried Greek oregano, preferably wild, crushed with your fingers into powder
- 1 large bunch flat-leaf parsley, stems removed, washed and dried
- 1½ sticks unsalted butter, softened to room temperature
- 2 tablespoons smashed and chopped garlic (6 to 8 cloves)
- 2 teaspoons salt plus more to taste
- 1 teaspoon black pepper plus more to taste
- 2 small red onions, peeled, halved, and cut into very thin long strips
- 1 heaping tablespoon sumac
- Three 10-inch rounds pita bread, cut in half
- 6 metal skewers
- In a mixing bowl, toss the beef with the olive oil and oregano, and let it stand while you prepare a charcoal grill and make the butter.
- Finely chop the parsley. Place it in a food processor, fitted with a metal blade, and process the parsley, butter, garlic, 2 teaspoons of the salt, and 1 teaspoon of the pepper until smooth. Place this mixture in a small bowl and set aside.
- Place the onions in a small mixing bowl and toss with sumac. Let this rest for a few minutes, to give the sumac a chance to pickle the onion somewhat.
- Using metal skewers, thread 4 cubes of marinated beef onto each and season with salt and pepper.
- Over medium-high heat, grill each side of the beef for about 4 minutes until brown.
- Remove the beef from the heat and place each skewer on a half of pita bread so that the pita bread catches the juice while it’s resting.
- Immediately, dollop each skewer with 1 tablespoon of the soft parsley butter so that it soaks into the meat and bread. You can freeze the extra butter or wrap it tightly in plastic wrap and store it in the refrigerator.
- Remove the skewers and top the pita and beef with a generous amount of sumac onions.