In the last decade, Autism Spectrum Disorder (ASD) prevalence rate has significantly increased, which consequently led to the expansion of research and expenditure in the field, predominantly focusing on searching for the cause. In a typical classroom scenario, working with children with ASD very often requires 1:1 teacher to child ratio, which makes it very expensive and difficult to implement. Serious games have been utilised as a medium for teaching various developmental skills, such as social interaction, speech, motor skills development, emotion recognition, and other basic concepts. Designing serious games for ASD population differs from other games and even other serious games significantly. It requires a holistic approach with extensive knowledge and expertise from fields other than computer science, such as psychology, sociology and cognitive science. However, once harnessed correctly, such games can be used by children with ASD on their own time, with or without supervision and they can be educational. In addition, they can adjust the appropriate pace while at the same time providing feedback in form of reinforcement and correction. Applying the rules of science of learning and teaching, one can design games that are educational for all types of learners, including children with ASD. In this paper, two independent user studies have been conducted, demonstrating how serious gaming and e-learning principles can be harnessed in order to intervene, develop or strengthen pivotal developmental skills, like learning novel vocabulary, counting, identifying numbers and colours, and responding to inference questions. We have tested the educational e-book with children diagnosed with ASD