Preheat and prep: Preheat your oven to 400°F (200°C). Pat the cod dry with paper towels and season both sides lightly with 3/4 teaspoon kosher salt and 1/4 teaspoon black pepper. Drying the fish removes surface moisture so the lemon-garlic dressing clings and the fish bakes rather than steams.

Make the lemon-garlic herb topping: In a small bowl combine 2 tablespoons olive oil, the minced garlic, the lemon zest and about 2 tablespoons lemon juice, the chopped parsley, and a pinch of red pepper flakes (if using). Whisk to emulsify. This cold emulsion will be spooned over the fish; the acid brightens the cod while the oil carries aromatics and helps the fish brown in the oven.

Start the brown rice pilaf: Rinse 1 1/3 cups dry brown rice under cold water until water runs mostly clear to remove excess surface starch—this prevents gummy rice. In a medium saucepan, heat 1 tablespoon olive oil and 1 tablespoon butter over medium heat. Add the finely diced onion and a pinch of salt and sweat, stirring occasionally, until the onion is translucent and fragrant (about 4–5 minutes). Sweating extracts and softens the onion’s natural sugars to build savory-sweet depth in the pilaf.

Toast and simmer the rice: Add the rinsed rice to the pan and toast for 1–2 minutes, stirring constantly—this toasts the grain, deepening its nutty flavor and helping the kernels stay separate. Add 3 1/3 cups low-sodium stock, bring to a vigorous simmer, then reduce heat to low, cover tightly and cook undisturbed for 35–40 minutes (or until liquid is absorbed and the rice is tender). Avoid lifting the lid early—steaming is how brown rice finishes cooking evenly.

Dress the cod and bake: Place the seasoned cod fillets in a lightly oiled shallow baking dish or rimmed sheet. Spoon the lemon-garlic-parsley emulsion over each fillet, spreading to coat the top. Dot with the remaining 1 tablespoon butter in small pieces (this helps baste the fish as it cooks). Bake in the preheated oven 10–12 minutes, depending on thickness, until the fish flakes easily with a fork and reaches an internal temperature of 135–140°F (57–60°C). Baking at 400°F gives a gentle roast that cooks the cod quickly without drying it; the small pats of butter melt and create a glossy finish.

Finish the pilaf: When the rice is done, remove the pan from heat and let it sit covered for 5 minutes—this resting period lets steam finish cooking and firms the grains. Fluff with a fork and stir in the remaining tablespoon of chopped parsley, a squeeze of lemon (about 1 tablespoon) and a pinch of salt. The finishing lemon brightens the pilaf and ties flavors to the fish.

Sauté the spinach: While the fish bakes, heat a large sauté pan over medium-high heat and add 1 tablespoon olive oil. Add 1 clove minced garlic (reserve the rest for the fish topping) and sauté briefly for 20–30 seconds until fragrant—do not brown. Add the packed spinach in batches, tossing and stirring until just wilted (2–3 minutes total). Season with salt, freshly ground pepper and a squeeze of lemon. Cooking spinach quickly retains its vibrant color, tender texture and nutrients.

Plate and finish: Divide the rice pilaf among four plates, pile the sautéed spinach alongside, and gently transfer a baked cod fillet onto each plate. Spoon any pan juices from the fish over the fillet and garnish with the remaining chopped parsley and a lemon wedge. Let the fish rest for 1–2 minutes before serving—the short rest allows juices to redistribute for a moister bite.

Taste and adjust: Encourage tasting at the table—add a little more lemon juice or a pinch of flaky sea salt to brighten the plate. A final grind of black pepper or tiny drizzle of extra-virgin olive oil can elevate the flavors.