Time Machine in El Capitan installer
The necessity for this is very limited. Here's the situation it will help with:


You don't have a working Recovery partition.
You have a bootable drive that boots to the Finder.
You don't want to—or can't—simply install a fresh copy of macOS onto your drive and restore from there.
You have a complete Time Machine backup (from which you did not exclude system files).
That Time Machine backup does not come with its own Recovery partition, as with a Time Capsule.


In order to do a Time Machine system restore on a drive without a (working) Recovery partition without installing macOS first, follow the following steps:


Obtain a macOS installer. You can download one from Apple's support site, but that didn't work for me. I was able to make this work with the version of El Capitan that's downloadable from the App Store.
Get access to a recovery partition. There are a few options:

2.1 Attempt to install macOS onto your computer. After it reboots, don't continue the installation; instead, restart into your bootable drive (TechTool eDrive, USB key, whatever you have).

2.2. Alternately, use Recovery Partition Creator (MacWorld has instructions).

2.3. Lifewire has another method. I've discovered that you can run Disk Utility 13 (that has the option of the Debug menu mentioned in the Lifewire article) in El Capitan if you hack it first.
If one of these options results in a working recovery partition, great! Boot into it and use that (in my experience option 2.1 will boot, but will not allow you to restore from Time Machine—at least in El Capitan). If not, continue to the next step.
Open the recovery partition. You can use the Debug menu in Disk Utility 13 or earlier (instructions in the Lifewire article above) to select and then mount it, or mount a disk image of the partition.
Use Tinkertool or some other method to show hidden files in the Finder.
On the Recovery HD (that you should have mounted on your desktop in Step 4) there is a folder called "com.apple.recovery.boot." In it is a hidden disk image named "BaseSystem.dmg." Mount that (I had to hit Command-O for some reason; double-clicking did not do the job). 
A disk image called "OS X Base System" will appear on your desktop.
Launch Terminal. 
Paste the following command, hit Return, then input your password when prompted: sudo -b /Volumes/OS\ X\ Base\ System/System/Installation/CDIS/Time\ Machine\ System\ Restore.app/Contents/MacOS/Time\ Machine\ System\ Restore (The reason for this is that Time Machine System Restore must be launched as root in order for it to properly restore your permissions.)
Follow the instructions to restore your system from your Time Machine backup!