What’s the best 30 minute workout when you’re crunched for time? Threshold? V02?
It depends on your goals! If you just need a recovery ride, Taku is the move. If you want to sharpen up the pointy end of your fitness, some high intensity workouts like the ones in our Time Crunch 30 plan will work great: https://www.trainerroad.com/cycling/plans/166-time-crunch-30-low-volume
Beware, these ones hurt.