Jacket potatoes with tuna mayo
Warm jacket potatoes topped with creamy tuna mayo
Allergens: contains eggs, fish. Brands differ, so always check the labels on what you buy.
Per serving (approx.): 45g carbs · 3g sugars · 8g fibre. Diabetes-friendly: no added sugar, 45g carbs or less and plenty of fibre per serving. 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 |
|---|---|---|---|
| Maris Piper potatoesuse 4 | £1.451.2kg · £0.12 per 100g | £1.802kg · £0.09 per 100g | £1.451.2kg · £0.12 per 100g |
| Tinned tuna in brineuse 1 tin | £0.65150g · £0.45 per 100g | £2.49568g · £0.43 per 100g | £2.20240g · £0.92 per 100g |
| Mayonnaisenot compared | – | – | – |
| Red onionpack 1kg · use 1 small | £0.95£0.10 per 100g | £0.95£0.10 per 100g | £0.95£0.10 per 100g |
| Basket total (full packs) | £3.05 | £5.24 | £4.60 |
| Cost of what this recipe uses | £1.74 | £3.27 | £3.27 |
| Per serving | £0.43 | £0.82 | £0.82 |
Not compared (a price wasn't found at every shop, so it isn't in the totals): Mayonnaise.
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.
- Wash the 4 Maris Piper potatoes thoroughly under cold running water, then pat them dry with a clean tea towel. Using a fork, prick each potato all over 6‑8 times to allow steam to escape. Rub each potato with 1 tbsp vegetable oil and a light pinch of salt, ensuring the skin is evenly coated.
- Pre‑heat the oven to 200 °C (fan 180 °C) and place a baking tray on the middle shelf. Lay the prepared potatoes on the tray, leaving space between them, and bake for 45‑50 minutes. They are ready when the skins are golden‑brown and crisp, and a skewer slides easily into the centre with little resistance.
- While the potatoes are in the oven, open the 1 tin of tinned tuna in brine and pour its contents into a sieve over the sink to drain excess liquid. Flake the tuna with a fork into a medium bowl, breaking up any large chunks. Peel and finely chop the 1 small red onion, then add it to the bowl.
- Add the 50 g of mayonnaise to the tuna and onion, then season with a pinch of salt and a grind of black pepper. Stir everything together until the mixture is uniform and creamy, scraping the sides of the bowl to incorporate all ingredients. Taste and adjust seasoning if needed, remembering that the potatoes will add a mild earthiness.
- After baking, use oven gloves to remove the tray and test a potato with a skewer; it should slide in easily and feel hot throughout. Let the potatoes stand on a wire rack for 5 minutes to cool slightly. Then cut a deep cross in each top and open the flesh with a fork.
- Spoon an even quarter of the tuna‑mayonnaise mixture into the opened centre of each potato, spreading it to fill the cavity. The filling should sit flush with the potato surface, showing a pale pink‑beige colour from the tuna. Repeat for all four potatoes, ensuring each receives the same amount.
- If desired, drizzle a tiny extra squeeze of lemon juice or a sprinkle of chopped chives over the tops for freshness. Serve the jacket potatoes immediately while hot, accompanied by a simple green salad or steamed vegetables if you like. Enjoy your meal.
Tips
- Swap the Maris Piper potatoes for sweet potatoes or use a mix to lower cost and add variety.
- Batch‑cook extra potatoes, cool them within 1‑2 hours, store in the fridge for up to 2 days, and reheat each portion in the microwave until steaming hot (only reheat once).
- For a lighter version, replace half the mayonnaise with plain Greek yogurt; it keeps the creaminess while cutting calories.
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.
- Maris Piper potatoes · about 200g left
Keep somewhere cool and dark (not the fridge). Use extras for mash, wedges or a traybake later in the week. Use it in: One-pan chicken, potatoes and veg, Beef & Veggie Skillet, Chicken and Sweet Potato Tray Bake. - Mayonnaise · about 450g left
Check the label: most raw ingredients can be frozen before their use-by date, and cupboard staples keep for months. - Red onion · about 895g 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.
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).