Block-based programming, already popular in computer science education, has been successfully used to make programming accessible to end-users in applied domains such as the field of robotics. Most prior work in these domains has examined smaller programs that are usually simple and fit a single screen. However, real block-based programs often grow larger and, because end-users are unlikely to break them down into separate functions, they often become unwieldy. In our study, we introduce a function-centric block-based environment to help end-users write programs that require a large number of blocks. Through a user study with 92 users, we evaluated our approach and found that while users could successfully complete smaller tasks with and without our approach, they were both quicker and more successful with our function-centric method when tackling larger tasks. This paper demonstrates that adding scaffolding can encourage the systematic use of functions, enabling end-users to write larger programs with block-based programming environments, which can contribute to the solution of more complex tasks in applied domains.