A recovery ride is the perfect time to work on your cadence.
Using a higher cadence during a recovery ride helps your recovery as you aren’t putting any stress through your muscles. Since it’s a good idea to be riding at a higher cadence (around 100rpm) during a recovery ride, why not up this a little to 110rpm and work on the fluidity of your cadence?
Riding with such a high cadence with almost no resistance on the pedals means you have nothing to push against and this helps to highlight any weaknesses in your pedal stroke. If you find yourself bouncing on the saddle then you know that there must be a dead spot in your pedal stroke causing you to bounce up and down.
Try doing blocks of five minutes at the maximum cadence you can sustain without bouncing in the saddle. You will probably need to concentrate on your pedaling technique in order to stay solid in the saddle, and once the block is over try and apply the same technique to your pedaling technique at your regular cadence.
Another way to integrate cadence drills into a recovery ride is to practice switching from one cadence to another. For example, switch between one minute at 120rpm and one minute at 100rpm. Repeat this five or times in a row. Doing this keeps your body guessing and should mean that your build up muscle memory quicker.