1. In a medium size bowl combine the lamb and beef. Season with salt/pepper.
2. Heat a pan over medium heat and cook the beef mixture for approximately 10 minutes, turning once.
3. Meanwhile toast the buns under a broiler until lightly browned.
4. Compile the burgers as follows: bun, mayo, mustard, onion, tomato, romaine, beef/lamb, feta, bun.
Makes 4 excellent burgers!