How to Make It
In a medium nonreactive skillet, heat 2 tablespoons of the oil. Add the burdock, shallot and garlic and cook over moderate heat, stirring often, until the burdock is golden and barely tender, about 15 minutes. Add 6 tablespoons of water, 1 at a time, and cook until nearly absorbed between additions. Add the soy sauce and remove from the heat. Cover and keep warm.
Make 3 small slashes about 2 inches long and 1/8 inch deep in the skin side of the bass fillets. Season both sides with salt and cayenne.
In a large nonstick skillet, heat the remaining 1 tablespoon of oil. Add the bass, skin side down, and cook over high heat until opaque around the edges, about 6 minutes. Gently turn the fish and cook for 1 minute on the other side.
While the fish is cooking, in a medium saucepan, melt the butter over moderate heat. Swirl in 3 tablespoons of water, 1 tablespoon at a time. Add the garlic mustard greens and cook, stirring, until just wilted, about 1 minute.
Spoon the burdock mixture onto 4 plates and top with a piece of fish, skin side up. Spoon the greens around the fish and serve.