Is it actually cheaper to cook it yourself?

A chilled ready meal is priced as a single serving. A jar of paste, a bag of rice and a bottle of oil are not. Comparing the shelf price of a €4.50 meal with a €22 shopping list and concluding that cooking is expensive is the most common mistake in this entire argument.

The honest calculation is: cost of the ingredients you actually used, at the portion size you actually ate. You need a real ingredient list to do it, which is the first step of the method anyway. That means dividing the jar by how many meals it gives, counting the two tablespoons of oil rather than the bottle, and counting the half onion rather than the net.

Do that once, properly, for a dish you cook often. The number is usually startling.

You need 100 g of cream cheese; it is sold in 200 g tubs. You need a tablespoon of tomato purée; it comes in a 140 g tube. You need half a bunch of coriander.

That leftover is the real enemy of home cooking economics — not because it costs much, but because it is thrown away. A saving that depends on using the other half is not a saving until you use the other half.

Three ways out, in order of how well they work:

1. Cook the dish twice in the same week, or in double quantity and freeze half. Overhang per portion drops immediately.
2. Plan two dishes that share the awkward ingredient. Half a tub of crème fraîche is a problem; a second dish that wants the other half is not.
3. Buy the format that matches the use. Tubes and frozen herbs cost more per gram and waste nothing, which frequently makes them cheaper in practice.

Copying pays best where the packaged version charges most for assembly and least for ingredients.

• Sauce-led dishes — curries, ragù, chilli, tikka masala, arrabbiata. Cheap ingredients, long cooking, high retail price. This is where the money is.
• Soups. Frequently the largest multiple of all; the ingredients are vegetables and stock.
• Traybakes and roasts. Almost no processing to pay for.
• Marinated proteins. You are paying a premium for a marinade that costs cents.
• Anything “premium” or “finest”. The step up in retail price is usually far larger than the step up in ingredient cost.

A rough guide from cooking these at home: sauce-led dishes commonly land at 40–60% of the retail price per portion, and soups lower still. The exact figure depends entirely on where you shop, so run it for your own basket.

Being honest about this is what makes the rest credible.

• Single portions of something complicated. One lasagne for one person is not cheaper. Four are.
• Dishes needing a specialist ingredient you will use once. A jar of a particular paste for one recipe wipes out the saving on that recipe entirely.
• Deeply discounted own-brand basics. A €1.80 own-label meal is priced below what its ingredients cost you at retail. That is scale, and you cannot beat it on cost. You can beat it comfortably on quality.
• Dishes needing long, energy-hungry cooking for one portion. Two hours of oven time is not free.

For those, copying is about taste, ingredients and control — which are decent reasons on their own.

A 400 g chilled tomato-and-mascarpone pasta meal, at a typical Western European supermarket price of around €4.00 for one portion. Cooking the same dish for four:

That is about €1.15 a portion against €4.00 — and the home version has roughly 200 g on the plate rather than 400 g of which a third was water.

Two caveats, honestly. Energy costs something: twenty minutes on a hob is real but small, and cooking four portions at once amortises it. And the mascarpone overhang is only zero because the dish uses most of the tub — which is exactly the point about choosing recipes that finish what they open.

A ready meal is eight minutes, most of it unattended. A copy might be forty, of which twenty need you in the room.

That is a real cost, and the honest way to think about it is per batch rather than per meal. Cooking four portions of a ragù takes barely longer than one, so the marginal cost of portions two, three and four is close to zero minutes and close to a third of the ingredient price. Batch cooking is the single change that makes home copying win on both money and time — and it works precisely because the awkward overhang gets spread across four meals instead of one.

Cooking four portions also lets you decide what a portion is, which turns out to matter more for the healthier version than any ingredient swap does.