Coat base of medium frying pan with cooking-oil spray; heat over medium heat. Place one tortilla in pan; sprinkle with one-quarter of the cheddar cheese, one-quarter of the ham and one-quarter of the feta cheese. Top with another tortilla, spray with oil.

Cook quesadilla in pan, pressing down firmly with a spatula, about 1 minute or until base is browned. Place a plate over frying pan and turn quesadilla onto plate. Slide quesadilla, uncooked-side down, back into pan. Cook 1 minute or until browned. Transfer to plate.

Repeat to make three more quesadillas; cut into wedges to serve.