- 1 teaspoon white wine vinegar
- 3/4 cup plus 3 tablespoons water
- 8 baby bok choy, trimmed, cut lengthwise in half through core
- 2 tablespoons chopped fresh tarragon
- 4 (7- to 8-ounce) tilapia fillets
Boil first 4 ingredients in heavy small saucepan until liquid is reduced to 2 tablespoons, about 9 minutes. Cover and remove from heat. DO AHEAD Can be made 4 hours ahead. Let stand at room temperature.
Prepare barbecue (medium-high heat). Combine 3/4 cup water and bok choy in large pot. Cover and cook over high heat until crisp-tender, turning occasionally, about 5 minutes. Drain. Sprinkle bok choy with sea salt and pepper. Cover to keep warm.
Whisk egg yolks and 3 tablespoons water in medium metal bowl. Set bowl over saucepan of barely simmering water. Whisk until mixture is light and foamy and thermometer inserted into center registers 160°F, about 2 minutes. Whisk in shallot-wine reduction and chopped tarragon. Season sabayon with salt and pepper. Remove from heat.
Immediately sprinkle fish with sea salt and pepper; brush with canola oil. Grill until slightly charred and just opaque in center, about 3 minutes per side.
Divide bok choy among 4 plates. Place tilapia alongside bok choy. Spoon warm béarnaise sabayon over fish.