Using an electric juicer or blender, juice celery, spring onion greens, cucumber and spinach together until very smooth (adding a little water if using a blender). Strain liquid through cheesecloth or a fine-mesh sieve to make roughly 1½ cups. Combine juice and créme fraîche in a small sauce pot and set aside.
In another small pot mix beans, peas and fava beans together with vegetable stock and slowly warm. Season to taste with salt and pepper.
Heat a large sauté pan and add oil. Season fish with salt and pepper. Sear fillets on one side for 4–5 minutes. Flip and cook on the other side for 6–8 minutes, depending on the thickness of the fish.
When the fish is cooked, season the juice with salt and pepper to taste and warm it over a low-medium heat, saving this for last to preserve the bright green color. Divide warmed beans and fish among 6 warm, shallow bowls. Pour broth around beans and fish. Garnish with radish.
Recipe by Christopher Bender and David Crowell, Chef/Owners, Stoneacre Pantry, Newport