Grilled Striped Bass with Plums and Potato-Mushroom Papillotes

• FAST
• HEALTHY

Ingredients

1. 1 pound fingerling potatoes, scrubbed
2. 1/2 pound hen-of-the-woods or oyster mushrooms, thickly sliced lengthwise
3. 1 tablespoon plus 1 teaspoon tamari
4. 1 tablespoon plus 1 teaspoon balsamic vinegar
5. 3 tablespoons extra-virgin olive oil
6. Salt and freshly ground pepper
7. Four 6-ounce striped bass fillets, skinned
8. 2 teaspoons chopped rosemary
9. 4 round purple plums, halved and pitted
10. Watercress sprigs, for garnish

1. Light a grill. Preheat the oven to 500°. In a medium saucepan of boiling, salted water, cook the potatoes until tender, about 10 minutes. Drain and let cool. Peel the potatoes and halve them lengthwise.
2. Tear off four 20-by-14-inch sheets of parchment or foil. Spread equal amounts of potatoes and mushrooms on half of each sheet. In a small bowl, mix the tamari with the vinegar and 1 tablespoon of olive oil. Drizzle over the potatoes and mushrooms and season with salt and pepper. Fold the sheets over the vegetables and crimp to seal, if using parchment; if using foil, fold in the edges to seal the packages. Transfer the papillotes to 2 baking sheets and bake for about 15 minutes, or until sizzling.
3. Drizzle the bass fillets with 1 1/2 tablespoons of the olive oil, sprinkle with the rosemary and season with salt and pepper. Drizzle the plums with the remaining 1/2 tablespoon of olive oil. Grill the bass over high heat until nicely charred and just cooked, 3 to 4 minutes per side. Grill the plums, cut side down, until lightly charred, about 2 minutes per side.
4. Transfer the bass fillets and plums to plates. Set a papillote on each plate and open it, pouring out the potatoes, mushrooms and any juices. Watch out for the hot steam. Serve garnished with watercress.