Add 1 1/2 cups water to the inside of pressure cooker. Place the trivet in bottom of pot.
Mix all ingredients together and form into four patties. Wrap each patty in foil. Place wrapped patties on trivet inside cooker.
Place the lid on the pot and set steam release valve to the sealing position. Cook on high pressure for 10 minutes. When the cook cycle is finished, do a quick release and open the steam valve.
Carefully remove patties using tongs. Let rest a minute then peel open foil and serve with toppings as desired (tomatoes, spinach, mustard).