Spanish omelette
A simple, hearty omelette made with potatoes, eggs and onion, cooked slowly until set.
Allergens: contains eggs, milk. Brands differ, so always check the labels on what you buy.
Per serving (approx.): 25g carbs · 3g 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
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| Ingredient | Tesco | Sainsbury's | Morrisons |
|---|---|---|---|
| Potatoesuse 500g | £1.562kg · £0.08 per 100g | £1.322kg · £0.07 per 100g | 2 × £0.85300g · £0.28 per 100g |
| Onionuse 150g | £0.951kg · £0.10 per 100g | £0.951kg · £0.10 per 100g | £1.30420g · £0.30 per 100g |
| Eggspack 6 pack · use 4 | £1.80£0.30 each | £2.40£0.40 each | £1.80£0.30 each |
| Semi skimmed milkuse 50ml | £0.85568ml · £0.15 per 100ml | £0.85568ml · £0.15 per 100ml | £0.85568ml · £0.15 per 100ml |
| Basket total (full packs) | £5.16 | £5.52 | £5.65 |
| Cost of what this recipe uses | £1.82 | £2.18 | £3.12 |
| Per serving | £0.46 | £0.54 | £0.78 |
From your cupboard
Not in the prices above. Check you have these before you start.
Prices checked on 4 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.
- Peel 500g potatoes and cut into 3mm-thick slices using a mandoline or sharp knife; peel 150g onion and slice into thin half-moons. Place both in a colander, rinse under cold water to remove excess starch, then pat thoroughly dry with kitchen paper — this prevents splattering and helps even browning.
- Heat 4 tablespoons vegetable oil in a 20cm non-stick frying pan over medium heat until shimmering but not smoking. Add the potatoes and onions, spreading evenly, and cook for 12–15 minutes, stirring gently every 3 minutes, until the potatoes are tender when pierced with a knife and the onions are translucent and sweet-smelling, with no brown edges.
- While the vegetables cook, crack 4 eggs into a large jug, add 50ml semi-skimmed milk, ½ teaspoon salt and ¼ teaspoon black pepper. Whisk with a fork for 30 seconds until the yolks and whites are fully combined and the mixture is pale yellow with a few bubbles on top.
- Using a slotted spoon, lift the cooked potatoes and onions from the pan, draining excess oil back into the pan, and tip them into the egg mixture. Stir gently to coat every piece, then let sit for 2 minutes so the potatoes absorb some egg — the mixture should look thick and clingy.
- Wipe the pan clean with kitchen paper, return 1 tablespoon oil, and heat over medium-low for 1 minute. Pour in the egg-potato mixture, spreading evenly with a spatula, and cook for 4–5 minutes until the edges are set and golden underneath but the centre still wobbles slightly when shaken.
- Place a large flat plate (wider than the pan) over the pan, hold firmly, and invert confidently so the omelette lands cooked-side up on the plate. Slide it back into the pan uncooked-side down, tuck the edges with a spatula, and cook a further 3–4 minutes until firm to the touch and golden brown.
- Slide the finished omelette onto a board, let rest for 5 minutes — this finishes the cooking gently and makes slicing clean. Cut into 4 wedges, taste a corner for seasoning, and serve warm or at room temperature with a simple green salad.
Tips
- Swap half the potatoes for 250g frozen peas (thawed) to cut cost and add colour; add them with the onions in step 2.
- Batch-cook two omelettes, cool within 1 hour, wrap wedges individually in foil, and freeze for up to 1 month. Defrost overnight in the fridge, then reheat once in a 180°C oven for 10 minutes until steaming hot throughout.
- For a lighter version, use 1 tbsp oil to soften the vegetables in a covered pan with 2 tbsp water for 10 minutes, then proceed — saves 120kcal per serving.
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.
- Potatoes · about 1.5kg 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. - 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. - Semi skimmed milk · about 950ml left
Keep in the fridge and use by the date on the pack; milk can also be frozen. Use it in: Rich Chocolate Mousse, Beef and Ale Pie, Banana muffins.
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).