Heat the oil until hot in the Instant Pot using the sauté setting, or in a large pan over a moderate heat.
Add the onion and fry gently for 3-4 minutes until softened but not browned.
Add the garlic and fry for another 1-2 minutes before adding the oregano and bay leaves.
Add the pork and stir to coat everything. Season with the salt and then pour in 700ml/23oz of water.
For Instant Pot: Put on the lid and set to pressure cook for 30 minutes.For stove top: Bring to a boil, then reduce the heat to low, cover the pan and simmer gently for 1½ hours until the pork is soft.
Remove the lid and then pour in the hominy and liquid. Return the pan to the heat (or sauté setting if using the Instant Pot) and bring to a boil. Cook for 5 minutes then remove from heat and serve.
Serve hot in bowls and garnish with the white onion, a drizzle of sour cream, a scattering of cojita cheese and a few radish slices.