To make the patties, soak the chickpeas overnight. In the morning, pressure cook until the chickpeas are soft and cooked and then set them aside.. You should be able to mash them easily when you press them between your thumb and index finger. If using an Instant Pot, cook on high pressure for 20 minutes with natural pressure release. If using a stove-top pressure cooker, do 1 to 2 whistles on high heat, then lower the heat and cook for 7-8 minutes more.