fastest to rebuild the linux kernel using rpmbuild

I just built the linux kernel for CentOS using the instructions that can be found here: https://wiki.centos.org/HowTos/Custom_Kernel

Now, I made my changes and I would like to rebuild the kernel and test it with my changes. How do I do that but: 1. Without having to recompile everything. So, build process should reuse whatever object files generated by the first build that wont need to be modified. 2. Without having to build the other packages that are build with the kernel (e.g., debuginfo, tools, debug-devel, ...etc.).

Thanks.