1 lb ground beef
1 pkg dried onion soup mix
4 pita pockets
Mix the ground beef and onion soup mix. Divide in four and make into burger-shape. Dig a hole in each one and press a chunk of feta in the middle, closing the meat over it.
Fry them up.
Open the pita pockets and stick a couple of slices of tomato, maybe 4 slices of cucumber and a piece of lettuce in each one.
When the burgers are cooked, put one in each pita.
Put a dollop of tzatziki in on top.
Best burger ever! Bonus: cooks through pretty easily since the core is cheese not beef.