Hail,
When recording, is it important to have a back drumhead on the bass drum?
I have only one drumhead (on the kicking side) for the moment, and I wonder if the sound could be improved with a drumhead on the back side.

You'll get more volume and more low end. Wether that would be an improvement depends entirely on your room, your other instruments and their settings, your other gear, and your mix.

I usually record without. I try to focus on capturing the attack. A nice trick if you find you have too little sub bass in your basdrum is creating a seperate track in your daw with a sine generator set at about 50hz, and throw a gate on there that opens and closes per sidechain from the kickdrum track.

Ok, you mean a separate track to simulate the sound of the back drumhead?

Yes, it can. There's plenty of information readily available about how resonant heads work on drums as well as how they can be used/varied to control the sound, so I won't go into detail on it.