Measure and rinse the brown rice. Rinsing removes loose surface starch and prevents gummy rice. Place 240 g (about 1 1/3 cups) dry brown rice in a fine-mesh sieve and rinse under cold water until the water runs clear. Drain well.

Cook the brown rice with scallion whites. In a medium saucepan, combine rinsed rice with 480 ml (2 cups) water or low-sodium broth and a pinch of salt. Bring to a simmer over medium-high heat, then lower to a gentle simmer, cover, and cook 38–40 minutes (brown rice requires longer cooking to become tender). Cooking now lets the rice finish while you prepare the fish and bok choy. After cooking, remove from heat and let rest covered 8–10 minutes to steam; fluff with a fork and stir in the sliced scallion greens (reserve some for garnish).

Make the miso-maple glaze. In a small bowl whisk together 4 tbsp white miso, 4 tsp maple syrup, 2 tsp grated fresh ginger, and 2 tsp light soy sauce until smooth. Miso is salty and rich—whisking with maple balances the savoriness and creates a glaze that will caramelize when seared. Set aside 1 tsp of the glaze for finishing (keeps a bright contrast on plating).

Prep the sea bass. Pat fillets dry with paper towels—dry surface = better sear and prevents sticking. If skin-on, use a sharp knife to score the skin lightly (2 shallow slashes) to prevent curling. Season the flesh side lightly with salt and pepper. Spread about 1 tbsp of the miso-maple glaze over the top (flesh) of each fillet—do not put glaze on the skin side (sugars can burn). Let sit 5–8 minutes at room temperature while you heat the pan; this short rest allows flavors to adhere and the fish to come closer to room temp for even cooking.

Steam the bok choy. Halve larger heads lengthwise so pieces are similar thickness. In a wide skillet fitted with a lid (or a steamer basket), add 2–3 tbsp water and the bok choy, cut-side down for maximum contact. Cover and steam over medium heat 3–5 minutes until just tender but still bright green—this preserves crunch and nutrients. Immediately drizzle with 2 tsp sesame oil and 2 tsp light soy sauce, toss gently, and sprinkle 2 tsp toasted sesame seeds so they stick to the warm leaves.

Preheat a heavy skillet (preferably cast-iron) over medium-high heat with 1 tbsp neutral oil. A properly preheated pan gives immediate contact heat so the fish skin crisps quickly rather than stewing. Oil should shimmer but not smoke.

Sear skin-side down first. Gently place each fillet skin-side down and press lightly with a spatula for 10–15 seconds to ensure even skin contact; this prevents the skin from curling. Cook skin-side down 4–6 minutes depending on thickness until the skin is deeply golden and releases easily from the pan. You are creating Maillard browning (flavor) and a contrasting crisp texture.

Flip and finish the fillets. Carefully flip each fillet and cook flesh-side 1–2 minutes until the glaze caramelizes and the fish is opaque to the center (internal temperature about 125–130°F / 52–54°C for moist, just-done sea bass). Avoid overcooking—sea bass is lean and will dry if held too long. In the last 20–30 seconds, brush the reserved 1 tsp glaze over the top and let it gloss and set.

Finish and plate. Spoon a bed of scallion brown rice onto warm plates. Nestle a glazed sea bass fillet on top. Arrange steamed sesame bok choy to the side. Scatter additional sliced scallion greens and a light sprinkle of toasted sesame seeds over the fish and rice. If desired, drizzle an extra ¼ tsp sesame oil and a few drops soy around the plate for aroma.

Serve immediately. Hot fish with warm rice and freshly steamed bok choy delivers the best texture contrast—crispy skin, tender flesh, nutty rice, and bright greens.