cd /usr/src/linux-X.Y
# copy the configuration of the running kernel:
cp /boot/config-$(uname -r) .config
make oldconfig
fakeroot make-kpkg --initrd --append-to-version=-custom kernel-image kernel-headers
cd ..
ls -lrt *-custom*deb
# only install the latest *-custom*deb here:
sudo dpkg -i *-custom*deb