Dr. Antonia,
One way is to have the students do a one minute paper on a topic that you want to see if they have retained content about. Have them write for 60 seconds about what they have learned, what they know, or what surprised them most about what has been covered. The 60 second time limit keeps it short in terms of class time and short in terms of student writing so they don't feel overwhelmed by having to answer with a major essay.
Gary
Gary Meers, Ed.D.