1. Boil or steam the potatoes for 15 to 20 minutes until tender.
2. Drain the potatoes and set aside to one side. In a pan, heat the oil and fry the garlic for 30 seconds.
3. Tip in the potatoes and crush roughly with a masher or fork until the skins split. Stir in the olives and parsley and season well with freshly ground black pepper.
4. Combine all of the salad dressing ingredients, leaving the spinach to go in just before serving.
5. Skin and trim the whole fish and season the fillets.
6. Place a non-stick frying pan over a medium heat until hot. Add the butter and when foaming add the fillets, bone side down.
7. Cook for 45 seconds to a minute, until golden, carefully turn over and cook for a further 45 seconds until golden on the other side.
8. Transfer the cooked fillets onto a warm plate. Add the capers to the pan and swirl around in the butter, and add some chopped flat-leaf parsley and lemon juice. Pour over the fish and serve with the lemon wedges and the potato crush.
9. Add the spinach to the salad dressing and serve.
Recipe courtesy of Lesley Waters