Cover pan tightly with foil, turning foil under the edge of pan. Set pan in pressure cooker so that it has enough water to come up to middle of pan. After the pressure builds,cook for 20 minutes. Turn off burner until pressure goes down. Remove pan from pressure cooker and set in refrigerator to cool.(Usually overnight) When cool, run knife around the edge of pan to free flan from sticking. Flip pan over and let sit so as much of the caramelized sugar drips out of the pan.