Watch how it’s made
Every step in 1:12 — from the ingredients to the finished dish.
Cod is the leanest thing in this collection. A six-ounce fillet carries around 30 grams of protein, under a gram of fat and no carbohydrate at all. That makes this the lightest dinner here at 285 calories, and it is the one to reach for on a day when the rest of what you have eaten has been heavy.
Being that lean is also its problem. Cod has almost no fat to protect it, so the margin between perfectly cooked and dry is narrower than with salmon.
Dry the fish properly
This matters more with cod than with any other fish here. It holds a lot of water, and water on the surface turns to steam in the oven, which is how a fillet ends up pale and slightly rubbery instead of firm and flaky.
Pat it dry with paper towel, then leave it uncovered on a plate in the refrigerator for twenty minutes if you have the time. The surface dries further and it roasts rather than steams.
Twelve minutes, not fifteen
At 425F a six-ounce fillet needs ten to twelve minutes. Cod flakes into large opaque pieces when it is ready, and the flakes separate cleanly.
Once it starts releasing white liquid onto the tray it has gone past. That white substance is albumin, a protein squeezed out of the flesh as it contracts, and it is a reliable signal that the fish is overcooked.
Green beans want the head start
Green beans need about eighteen minutes to go from squeaky to properly roasted with blistered edges. The cod needs twelve. Start the beans alone for six minutes and add the fish after.
Roasted green beans are a different vegetable from boiled ones. The dry heat concentrates them and the edges crisp; boiled, they are simply soft and green.
Lemon on top, not underneath
Slices laid over the fillets perfume the fish as they roast and keep the surface from drying. Placed underneath they steam it from below, which is the opposite of what you want.
Keep half the lemon back and squeeze it over at the end. Roasted lemon is mellow and sweet; raw lemon is sharp, and the sharpness is what lifts a lean white fish.
What to add if it is not enough
At 8 grams of carbohydrate there is plenty of room. A small baked potato adds about 30 grams, half a cup of quinoa about 20, and either turns this into a substantial plate.
Or add a second fillet. Protein is the cheapest way to make this filling without touching the carbohydrate at all.