You should reuse your C++ code from one project to another to speed up your workflow.
According to this post on the Unreal Engine Forums,
- Copy your .h and .cpp files from the original project and paste them into a project of your choice (I suggest having the project closed before you do that).
- Go to your header files and change the project module name i.e. “EXAMPLEPROJECT_API” to the project API you’re importing the code into.
- Make sure the new code compiles.
- Finally, delete the Intermediate and Binaries folder.
- Then re-generate your project files by right clicking your .uproject file and click on the Generate Visual Studio Project.