Mix together the oil, spices, thyme and garlic in a non-metallic dish. Add the pork steaks, turn and coat well. Cover with clingfilm and marinate for at least 10 minutes or overnight.
For the stew, fry the chorizo in a medium-sized pan for 3-4 minutes or until golden brown. Remove and set aside.
Add the onion to the pan and fry for 2-3 minutes or until softened. Add the garlic and fry for a further minute. Add the sherry or white wine (if using), then turn up the heat and let it boil for 1-2 minutes to cook off the alcohol. Return the chorizo to the pan with the stock and butterbeans, bring to the boil and then simmer for 10 minutes or until the liquid has reduced by half. Stir in the parsley.
While the butterbean stew is cooking, heat a griddle pan until smoking hot. Brush most of the marinade off the steaks (to prevent it burning) and griddle the steaks for 2-3 minutes on each side, until just cooked through and golden. To serve, divide the stew between 4 bowls and top with the griddled pork.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.