Ingredients
TZATZIKI SAUCE:1/2 cup plain yogurt1/2 medium cucumber, peeled, seeded and finely chopped1/2 cup sour cream1 tablespoon crumbled feta cheese1-1/2 teaspoons olive oil1 garlic clove, minced1 teaspoon red wine vinegar3 fresh mint leaves, choppedBUNS:1/4 cup butter, softened1 teaspoon dried basil1 garlic clove, minced6 hamburger buns, splitBURGERS:1 medium onion, finely chopped1/4 cup crumbled feta cheese6 garlic cloves, minced1 tablespoon dried marjoram1 tablespoon dried rosemary, crushed1 teaspoon salt1/2 teaspoon coarsely ground pepper2 pounds ground lambTOPPINGS:2 medium ripe avocados, peeled and slicedLettuce leaves, red onion slices and/or tomato slices, optional
Preparation
Line a strainer with four layers of cheesecloth or one coffee filter and place over a bowl. Place yogurt in strainer; cover yogurt with edges of cheesecloth. Refrigerate for 2 hours.
Remove yogurt from cheesecloth and discard liquid from bowl. Pat cucumber dry with paper towels. In a small bowl, combine the yogurt, cucumber and remaining sauce ingredients. Cover and chill until serving.
In a small bowl, combine the butter, basil and garlic. Spread over cut sides of bun; set aside.
For burgers, in a large bowl, combine the first seven ingredients. Crumble lamb over mixture and mix well. Shape into six patties.
Grill patties, covered, over medium heat or broil 4 in. from the heat for 5-7 minutes on each side or until a thermometer reads 160° and juices run clear.
Grill buns, cut sides down, over medium heat for 30-60 seconds or until lightly toasted. Serve burgers on buns with avocado, tzatziki sauce and, if desired, lettuce, onion and tomato.
