Depends on type, but generally, power off, stick full back, full rudder into the direction of the spin
So you want to do that to pick up a wing?!
Don't forget that while you are accelerating one wing you'll be decelerating the other. Maybe enough to induce a stall and, therefore, spin in the opposite direction to your wing drop.
how are you suppose to recover correctly if you have 90 degree bank due to a dropped wing
The same way you recover from 1 degree of bank, or 20, or 45 etc. Unstall the wing and apply power then ailerons to return to wings level.