Teaching using the Mastery Learning Approach involves delineating learning units and assessing each unit individually and repeatedly until a student obtains success. Mastery Learning has been shown to help students better identify and grasp fundamental concepts. We applied Mastery Learning in a second-year software construction course with roughly 450 students. We delineated 26 topics, and administered written and verbal quizzes to assess each topic. We built a quiz auto-grading, analysis, and feedback system to help cope with the scale of the class. By the end of the semester we had administered over 12K quizzes. We found evidence that students grasped both fundamental concepts and advanced concepts better than in prior semesters. Because we made two changes at once (introducing videos and Mastery Learning) it is difficult to isolate whether the Mastery Learning Approach was solely responsible, but assessment results suggest that the repeatable micro-quizzes were instrumental in these gains. Auto-grading and extensive data collection afforded us invaluable and lasting pedagogical insights because of the depth of analysis they made possible.