This is a really fast kick, which will break Uke's knee at up to 114% Dismemberment
Just do it all on one leg, and engage distance 100

Contract hip and knee

Extend ankle

Space

Extend knee

Contract Ankle

Done!

If done correctly, you should kick Uke's lower leg off.

D'oh! I forgot to say that it was only one leg you should use... :
Ill be correcting it now, but thanks anyway.