Different varieties of large white beans are grown all over the world. If you cannot find the dried Greek gigantes, other types of large white beans will do, such as Corona, La Spagna, or large limas. Whether you prepare the traditional Greek bean or one of its cousins, you will end
up with a warming and hearty dish. The beans are partially cooked and then simmered in an oregano-spiked tomato sauce and sprinkled with lots of feta cheese. Serve them with big hunks of crusty bread for sopping up all of the sauce.
Combine the beans, water, and salt in the Instant Pot. Leave the pot turned off and let the beans soak for 10 to 12 hours or up to overnight.
Secure the lid and set the Pressure Release to Sealing. Select the Bean/Chili setting and set the cooking time for 15 minutes at high pressure.
Let the pressure release naturally for 15 minutes, then move the Pressure Release to Venting to release any remaining steam. Open the pot, ladle out 1 cup of the cooking liquid, and set the liquid aside. Wearing heat-resistant mitts, lift the inner pot out of the Instant Pot and drain the beans in a colander. Return the now-empty inner pot to the Instant Pot housing.
Select the Sauté setting and heat the 1/4 cup olive oil in the pot. Add the garlic, onion, and celery and sauté for about 5 minutes, until the onion has softened. Add the drained beans, the reserved 1 cup liquid, the tomatoes, oregano, and pepper and stir well.
Secure the lid and set the Pressure Release to Sealing. Press the Cancel button to reset the cooking program, then select the Bean/Chili setting and set the cooking time for 5 minutes at high pressure.
Let the pressure release naturally for at least 15 minutes, then move the Pressure Release to Venting to release any remaining steam.
Ladle the beans into a serving dish. Sprinkle the parsley and feta cheese over the beans, drizzle with the remaining 2 tablespoons olive oil, and serve.