Adapted from Gourmet
For sambal vinaigrette
1 1/2 tablespoons rice vinegar (not seasoned)
2 teaspoons sambal oelek (Southeast Asian chile sauce)
1 1/2 teaspoons Dijon mustard
1/3 cup vegetable oil
For wasabi cream
2 teaspoons wasabi (green horseradish) powder
3 tablespoons water
1/4 cup sour cream
1 (2-lb) halibut steak (1 1/2 inches thick), skinned, boned, and cut into 4 pieces
1/4 cup finely chopped fresh parsley
1/2 tablespoon vegetable oil
Preheat oven to 400°F.
Blend vinaigrette ingredients in a blender until smooth. Season with salt.
Whisk together wasabi powder and water until smooth, then whisk in sour cream. Season with salt.
Pat fish dry and season with salt and pepper. Sprinkle 1 side of each piece with parsley.
Heat a well-seasoned cast-iron skillet over high heat until hot. Add oil, then fish, parsleyed sides up. Sear fish until undersides are browned, about 1 minute.
Turn fish over and put skillet in middle of oven. Roast until just cooked through, 4 to 5 minutes.
Serve fish, parsleyed sides up, with a spoonful of each sauce.