While the waffle iron heat up, lay open pita on your work surface. Spread mustard over half of the flatbread. Lay half of the cheese over one-half of the pita. Lay the ham on top, followed by the greens. Cover with the remaining cheese. Cover with the top of the pita.
Carefully set the pita in the center of the waffle iron and press the lid down firmly. Cook until the pita is lightly brown and crispy