Heat the oil and butter in a large, heavy-based saucepan over a medium heat, add the onion and garlic and fry for 8–9 minutes or until softened and lightly golden. Add the remaining vegetables and the herbs and stir for 10 minutes or until lightly golden. Remove with a slotted spoon and set aside.
Increase the heat to medium-high, add the monkfish and season with salt and pepper. Fry for 3–4 minutes, stirring occasionally, or until lightly coloured all over. It may be necessary to add an extra teaspoon of oil.
Return the vegetables to the pan, then pour over the wine and stock and stir gently. Bring to the boil, then reduce the heat, cover and simmer gently for 8–10 minutes or until the fish is cooked through and the vegetables are tender. Serve with steamed curly kale and crusty brown bread.