Fast? Well... 4-5 hours.
Put oven on 125 degrees Celsius.
Find a pot that works in the oven (preferably from the seventies and ugly brown).
Put the meat in the pot and add coriander.
Chop the garlic.
And onions and put on top of the meat. Also add the cumin.
Put BBQ-sauce on top.
Put in oven.
After 1 hour in the oven, push down the onions from the top of the steak to the bottom of the pot.
After 3-4 more hours in the oven, use two forks to divide the meat into "strings".
Serve with corn, salsa and sour cream.
And perhaps mashed potatoes.