Rinse beans and pick out any stones, pebbles, or non-bean materials.
If desired, soak in water overnight to reduce cook time, but this is not necessary.
Put beans into Instant Pot. Add water, onion, bay leaf, salt and pepper. Stir. Secure lid, turn valve to seal.
Set pressure cooker to 'pressure cook' or 'manual' (depending on model), high pressure, for 50 minutes for dry beans (15 minutes for soaked beans).
Let pressure release naturally (in other words, leave it alone) for 15 minutes.
Quick release any remaining pressure by turning valve to 'vent.' Remove lid.
Carefully remove bay leaf. Beans can be drained, or you can scoop beans out with a slotted spoon, or enjoy them with the cooking broth. It's delicious!
Serve, garnished with chopped cilantro, if desired.
