Heat the bread in a low oven. Heat the butter in a skillet and saute the
onion, garlic and pepper until just soft; do not brown. Add the beef,
mustard, oregano, salt and a generous amount of pepper. Cook, stirring,
until the meat is no longer red. At the last minute stir in the chopped
tomatoes and cook briefly. Cut the pitas in half and stuff the pouches.
