The fastest way to get lots of mushrooms (of any kind) is to use bulk substrates
, inoculated with a select strain from a clone which has evinced quick colonization as well as quick fruiting capabilities, and of course huge returns. You'd need a huge pressure cooker (well, probably an autoclave), and a warehouse ::grin::
To be honest, there is no quick and dirty way
to start producing massive flushes from the start. A multispore inoculation (say a spore syringe inoculation) can give very varying yields.
Most experienced cultivators select and isolate their strains based on big fruits or vigor of growth on agar plates. Another key point is understanding what the pinning triggers are, how they work and when to start fruiting conditions.
If you are new to growing mushrooms and are here with the intent on making a fast dollar you will come out very disappointed. You will probably fail at the first bulk grow. Do not start running if you never learned to walk.
PS This website does NOT condone the sale of mushrooms - so asking questions how to become a cash cropper will, at best, get ignored (and at worst, get you flamed an banned).
Save yourself the trouble :)