All tasks have a certain minimum amount of time to complete, and no amount of persuasion, management, pressure, technology, or people can change that.
Reducing development tasks to the barest minimum is to define completion as delivery of a reasonably stable component. Unit testing is simply not done. The QA department, or another person or organization becomes responsible for the vast majority of testing.
Automated testing tools can greatly speed the cycle of delivery, defect identification, and verification. This is one way to speed a project along.
Although it is likely there will be a lot of bugs, if the software has a good architecture, most will resolve quickly.
This approach does require experienced engineers, because in order to build good code fast, people need a wide skill set, good tools, and plenty of self-discipline.