Add a couple tablespoons of olive oil, a few pepper corns, and two bay leaves to the pressure cooker.
Put the pressure cooker on the stove over high heat.
We added several sliced up several mushrooms too as my bag of scraps didn't contain any mushrooms and from what I've read they really add to the flavor. We also added a few stocks of celery we had as well.
Saute the mushrooms and celery for a few minutes.
Add a cup of water and try to loosen the fond, scraping as much as possible off the bottom.
Add nine more cups of water, but be sure you aren't overfilling your pressure cooker. It shouldn't be filled more than 3/4 of the way full.
Secure the lid and bring the pot to pressure (our pressure cooker does 15 psi).
Cook for 45-60 minutes.
Remove from heat and allow the pressure to fall on its own accord.
Press everything through a funnel hand press (chinois) and tada! Stock!