In a small saucepan, combine vinegar, sugar, cloves, and bay leaf. Bring to a boil and then remove from heat. Place the onions in a small non-reactive container and cover with the pickling brine. Use the pickled onions after 1 hour or refrigerate for 1 week.
Roast the red pepper or use store-bought, prepared pepper.
Heat oven to 350°. Spread pistachios on a cookie sheet and toast for 3-5 minutes. Pulse pistachios in a food processor until ground into small pieces.
Place in a medium size-mixing bowl the cooled pistachios and roasted red pepper. Add the ground lamb, dried spices, red pepper flakes, and egg white. Thoroughly combine these ingredients by hand or by pulsing in a food processor. Allow the mixture to rest refrigerated for 30 minutes.
Remove lamb mixture from refrigerator and divide into 4 equal balls, which can be formed into 4 patties. Preheat your grill and season the patties with salt on both sides. Grill to your liking. Quickly grill the pita bread.
To serve, spread ¼ cup of yogurt on each patty, top with romaine, pickled onion, pickled peppers, and diced tomatoes.
Recipe courtesy of Trevi Café and Wine Bar in Mashpee Commons at 25 Market Street. This recipe also appeared in the 2013 Early Summer issue of Cape Cod HOME.