How to Make It
In a resealable plastic bag, combine the sea bass fillets and the mirin. Seal the bag and marinate in the refrigerator for 1 hour. Remove the fish from the marinade and pat dry.
Meanwhile, in a small saucepan of boiling water, simmer the garlic for 1 minute. Drain and let cool. Peel the cloves and thinly slice them lengthwise. In a small bowl, combine the tomato juice, vinegar and lemon juice.
Heat 2 tablespoons of the oil in a nonreactive medium skillet. Add the garlic and cook over low heat until golden, about 7 minutes. Using a slotted spoon, transfer the garlic to a bowl. Add the bok choy and ginger and cook over moderately high heat for 30 seconds. Add 2 tablespoons of water and toss until the bok choy is wilted, about 1 minute. Add the tomato juice mixture to the greens and cook for 1 more minute.
In a large heavy nonstick skillet, melt the butter in the remaining 2 tablespoons of oil. Season the fish with salt and white pepper and cook over moderate heat, turning once, until nicely browned on both sides and opaque throughout, about 3 minutes per side.
If necessary, rewarm the bok choy. Mound it on the plates, spooning the sauce around it. Sprinkle the bok choy with the garlic slices and top with the sea bass. Serve at once.