Bring a heavy based pan to a medium heat with a generous drizzle of avocado oil. Once hot, sauté the onion until it comes translucent. Set aside in a bowl.
Add some more oil to the pan, and fry the ham and potato until crispy and golden. Return the onions to the pan, and stir through with the Worcestershire sauce.
Sprinkle with parsley before serving, and top with a fried egg and avocado.