Preparation

• Supreme the grapefruit: Using a small, sharp knife, slice off a small section from each end of the grapefruit. Stand on a flat end and remove the rind and pith with a small, sharp knife, cutting in long strips. Remove each citrus segment by cutting to the right and left of each membrane and place them in a medium-sized bowl. Squeeze the juice from the membrane into a small bowl, reserving about 4 tablespoons of juice.
• Cut the fennel bulb into quarters and remove the core. Using a mandoline or very sharp knife, cut fennel lengthwise into paper-thin slices and place in the medium bowl with the grapefruit segments.
• Add the mustard to the grapefruit juice and whisk to combine in the small bowl. Whisk in ¼ cup olive oil.
• Pour half of the vinaigrette into the medium bowl with fennel and grapefruit and toss to combine.
• In a small food processor, combine drained beans and 1 tablespoon of mustard. Purée and add salt and pepper to taste.
• Lightly coat the halibut with oil and season with salt and pepper. Place in a skillet over medium heat, and cook for about 2 minutes per side, or until the fish is cooked through.
• To serve, place about 1/3 cup of puréed beans on a plate. Place halibut atop the beans and spoon the grapefruit and fennel slaw on top. Drizzle the remaining vinaigrette evenly on the fish.