Baked cod with tomatoes
A simple baked fish dish with tomatoes and cheese, perfect for a quick family dinner.
Allergens: contains fish, milk. Brands differ, so always check the labels on what you buy.
Per serving (approx.): 8g carbs · 6g sugars · 3g fibre. Estimates for carb counting, not medical advice. If you have diabetes, follow your GP or dietitian's advice.
Not every ingredient has a checked price at Asda, Aldi, Co-op, Iceland, so they aren't compared here yet (more are checked every day). Lidl doesn't publish prices online, so it can't be compared.
Ingredients and prices
Swipe the table to see every supermarket.
| Ingredient | Tesco | Sainsbury's | Morrisons |
|---|---|---|---|
| Salmon filletsuse 4 fillets | £4.50240g · £1.88 per 100g | £6.25220g · £2.84 per 100g | £4.15220g · £1.89 per 100g |
| Chopped tomatoesuse 1 tin | £0.45227g | £0.45400g | £0.39220g · £0.18 per 100g |
| Onionuse 1 onion | £0.951kg · £0.10 per 100g | £0.951kg · £0.10 per 100g | £0.953 pack · £0.32 each |
| Unsalted butterpack 250g · use 25g | £1.85£0.74 per 100g | £1.85£0.74 per 100g | £1.85£0.74 per 100g |
| Grated cheeseuse 100g | £2.50250g · £1.00 per 100g | £2.50250g · £1.00 per 100g | £1.89250g · £0.76 per 100g |
| Basket total (full packs) | £10.25 | £12.00 | £9.23 |
From your cupboard
Not in the prices above. Check you have these before you start.
Prices checked on 5 October 2026 from each supermarket's own listing or a price-comparison site. Each shop's unit price (or pack size) is shown under its price, and "cost of what this recipe uses" compares like with like (tap a price to see its source). Cheapest in each row is ticked. Prices, offers and pack sizes change; loyalty-card prices are not included unless stated.
Method
The method is written for 4. For a different number, use the amounts in the table above.
- Preheat the oven to 200°C (fan 180°C) and line a baking tray with parchment. Pat 4 salmon fillets dry with kitchen paper, then season both sides with a pinch of salt and black pepper. Place the fillets skin‑side down on the tray.
- While the oven heats, peel and finely chop 1 medium onion. Heat 1 tbsp vegetable oil in a medium saucepan over medium heat, add the onion and cook 4‑5 minutes until softened and translucent, stirring occasionally.
- Add the entire 400 g tin of chopped tomatoes to the pan, stir in 25 g unsalted butter cut into small pieces, and simmer gently for 6‑8 minutes until the sauce thickens slightly and the butter has melted, giving it a glossy appearance.
- Season the tomato sauce with a pinch of salt, a grind of black pepper, and, if you like, a teaspoon of sugar to balance acidity. Taste and adjust; the sauce should be rich, slightly sweet, and coat the back of a spoon.
- Spoon the hot tomato‑butter sauce evenly over each salmon fillet, making sure the fish is mostly covered but the edges remain visible. Sprinkle the 100 g grated cheese over the top, distributing it so it melts into a golden crust.
- Transfer the tray to the pre‑heated oven and bake for 12‑15 minutes, or until the salmon is opaque throughout and flakes easily with a fork, and the cheese is bubbling and lightly browned.
- Remove from the oven, let the dish rest for 2 minutes, then serve each fillet with a spoonful of the tomato sauce and a side of steamed greens or crusty bread. Enjoy while hot.
Tips
- For a cheaper version, use frozen salmon fillets (thawed) and a strong cheddar instead of the grated cheese.
- Double the recipe, divide into four portions, cool within 1‑2 hours and refrigerate; eat within 48 hours or freeze for up to 1 month.
- To reheat, thaw frozen portions in the fridge overnight, then heat in a 180°C oven until steaming hot throughout (about 15‑20 minutes); reheat only once.
Nothing wasted: your leftover ingredients
Supermarkets sell set pack sizes, so you'll have some ingredients left. Here's how to keep them, and other recipes here that use them up.
- Onion · about 850g left
Chop the rest and freeze it flat in a bag: it cooks straight from frozen in soups, curries and sauces. Whole onions keep for weeks somewhere cool, dark and dry. Use it in: Chilli con carne, Egg fried rice, Creamy Tomato & Hidden Veg Pasta Bake. - Unsalted butter · about 225g left
Check the label: most raw ingredients can be frozen before their use-by date, and cupboard staples keep for months. Use it in: Banana muffins, Ginger Cake, Pad Thai with Chicken. - Grated cheese · about 50g left
Keep wrapped in the fridge. Grate any extra and freeze it: it melts straight from frozen on pasta bakes and toasties. Use it in: Creamy Tomato & Hidden Veg Pasta Bake, Tuna and Sweetcorn Pasta Bake, Cheesy Bean & Rice Casserole.
Storing leftovers
Cool leftovers and put them in the fridge or freezer within 1–2 hours. Eat fridge leftovers within 2 days, or freeze them. Defrost in the fridge and reheat only once, until steaming hot all the way through (Food Standards Agency guidance).