Spiced Beef & Onion Pitas

We love pitas, and we had steaks left from the Safeway sale, so beef pitas seemed like a great recipe to try. This was fun for a more casual meal.

For sauce

3 cups loosely packed fresh flat-leaf parsley leaves (from 2 bunches)

2 tablespoons cider vinegar

2 tablespoons water

1 tablespoon chopped shallot

1 teaspoon sugar

1/2 teaspoon salt

1/4 teaspoon black pepper

1/4 cup olive oil
For beef and onion pitas

4 (6-inch) pita loaves with pockets

1/4 cup olive oil

1 lb white onions, quartered lengthwise, then cut lengthwise into 1/4-inch-wide wedges

3/4 teaspoon ground coriander

1/2 teaspoon ground cumin

1/2 teaspoon salt

1/4 teaspoon black pepper

1 lb 1/3-inch-thick top round steaks, cut into 1/3-inch-wide strips

Make sauce:Purée all sauce ingredients in a blender until smooth.

Make beef and onion pitas: Wrap untoasted pitas in foil and warm in a preheated 300°F oven or toaster oven.
Heat 1 tablespoon oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking, then sauté half of onions, stirring occasionally, until browned but still crisp, 4 to 5 minutes. Transfer to a large plate. Sauté remaining onions in 1 tablespoon oil in same manner and transfer to plate (reserve skillet).
Stir together coriander, cumin, salt, and pepper in a bowl. Pat beef dry and toss with spices. Heat 1 tablespoon oil in skillet over moderately high heat, then sauté half of beef, stirring, until browned but still pink inside, 1 to 1 1/2 minutes. Transfer beef to plate with onions, then sauté remaining beef in remaining tablespoon oil in same manner.
To serve:Halve pitas and fill with beef and onions. Serve sauce on the side.