Heat the oil in a large non-stick frying pan. Cook the onion for 3-4 minutes over a medium heat, or until golden brown. Add the potatoes, press down and continue to cook with the onion for 2-3 minutes without disturbing to achieve a crispy base.
Add the garlic, thyme, cayenne or chilli powder and season, if required. Reduce the heat and cook for about 5 minutes, or until meat is piping hot.
Add the mayonnaise and stir gently to combine. Serve the hash with a poached or fried egg and garnish with the parsley. Serve with a green salad and relishes or condiments of your choice.
Tip: This recipe works well with cooked roast lamb too.