For the guacamole blend the shallot and Jalapeño in a food processor. Add the flesh of the avocado, sour cream and lime juice and blend until very smooth. Season to taste and store in the fridge.
For the refried beans, sweat the onion off without colour until softened. Add the chorizo and cook for 3-4 minutes. Mash the beans and then add to the onion and chorizo, and continue to cook until hot. Add the chicken or vegetable stock until you have a smooth, creamy consistency. Season to taste and keep warm.
For the salsa, mix the diced tomato, onion and olives with the coriander, with a little olive oil to make a dressing.
For the halibut, pan fry the seasoned halibut steaks in olive oil until cooked, adding a knob of butter and squeeze of lemon at the end.
To assemble, make a bed of refried beans on a large plate, add a few tablespoons of guacamole next to it and slide through with a spoon. Place the halibut on top of the beans and drizzle the salsa lightly around the plate.