Slow-Roasted Salmon Salad with Barley and Golden Beets

Preheat oven to 325°F with a rack 6 inches from heating element and another in center. Season fish with salt and pepper; place in a broiler-proof skillet or baking dish, skinned-side down. Season lemon slices and scatter over top; drizzle 6 tablespoons oil over everything.

Roast on center rack until fish is almost cooked through but still translucent-pink in center, 18 to 20 minutes. Spoon some of oil from skillet over fish. Switch oven to broil; transfer to top rack and broil until lemons are lightly charred in spots and fish is just cooked through, 3 to 5 minutes more. Let cool slightly.

Meanwhile, using a mandoline or a sharp knife, slice beets into very thin rounds, about 1/8 inch thick (you should have about 2 cups). Season with salt and drizzle with oil. Let stand, stirring occasionally, until softened slightly, 10 minutes; drain.

Heat remaining 2 tablespoons oil in a large nonstick skillet over medium-high. Add beets and cook, stirring occasionally, 5 minutes. Add scallion whites and light greens; continue cooking until softened and lightly caramelized, about 5 minutes more. Remove from heat; season to taste and stir in lemon juice.

Toss beet mixture in a large bowl with barley and half of broiled lemon slices. Fold in 3/4 cup parsley and scallion dark-greens; season to taste. Mound on a platter and top with fish and remaining lemon slices; sprinkle with remaining 1/4 cup parsley and drizzle with a bit of oil from roasting skillet. Serve.