At the Alma 1 restaurant at KU Leuven, they clearly had chicken cutlets, but they absolutely refused to let you buy one separately, stipulating that you could only buy it as part of a set meal (5.6 euros for students).
If the set meal didn’t include the combination you wanted, and you just wanted to add something extra—for example, the set meal originally included a chicken cutlet, vegetables, and rice, but you only wanted the chicken cutlet—that was absolutely impossible there. You had to buy a whole set meal. But by then, I had already eaten lunch and couldn’t possibly eat a second one.