Creating an optimal CI/CD workflow with CircleCI involves overcoming challenges in configuring the infrastructure, where Docker layer caching (DLC) emerges as a significant technique to enhance efficiency. Docker, a containerization technology used on CircleCI, allows teams to build, test, and deploy applications in a consistent and collaborative manner by packaging everything into portable units, avoiding environment conflicts. Docker layer caching speeds up the process by saving and reusing Docker image layers so that unchanged layers don't need to be rebuilt in subsequent runs, significantly reducing build times and saving resources. This caching is particularly beneficial when the same image is built repeatedly in CI/CD pipelines, and it involves setting specific configurations in the config.yml file to enable it. While DLC provides noticeable efficiency improvements by reusing cached layers, it only impacts the time taken to build Docker images, not the time to initiate the primary Docker container. Furthermore, cached layers are retained for three days unless reused, and additional optimizations, such as dependency caching, can further enhance the pipeline's performance.