How to scale a recipe for a crowd without panicking

The first time I cooked for twenty, I did what any reasonable person with a calculator does. I took a chicken curry that fed four, multiplied every line by five, and wrote the new numbers in biro on the back of an electricity bill. Five times the chicken. Five times the onions. Five times the salt. Twenty green cardamom pods, which looked like a lot, but maths is maths.

Our flat at the time had a four-ring hob where only two rings really worked, and an oven roughly the size of a microwave. I'd borrowed a huge aluminium pot from my khala, the kind that lives on top of a wardrobe until someone gets engaged. I put it on the big ring, filled it with everything, and waited.

Forty minutes later, the bottom had caught, the top was lukewarm, and the whole flat smelled like a cardamom-scented candle. T took one spoonful, went quiet in a way I've since learned to fear, and said, "It tastes like a hotel lobby." We ordered from the place on the corner and told everyone it was a deliberate choice.

So this is the post I wish I'd read before that evening. Ingredient quantities mostly scale in a straight line. Almost everything else doesn't. Pan size, cooking time, oven temperature, whole spices and seasoning all need a little thought when you go from four portions to twenty.

What scales neatly

• Main ingredients: meat, vegetables, pulses, rice and pasta. If one person eats 250g of chicken on the bone, twenty people eat about 5kg. No clever adjustment needed.
• Onions, garlic, ginger and tomatoes. These are the body of a curry, not the seasoning, so they scale fully. Skimp here and you get a thin, sad sauce stretched over too much meat.
• Ground spices like turmeric, coriander and cumin, more or less. Give them a straight multiply and taste at the end.
• Liquids, usually, though a big pot loses less to evaporation than a small one. Add about two-thirds of the scaled water first and the rest only if it needs it.

What doesn't

• Oven temperature. Keep it the same. If a tray of potatoes roasts at 200°C (180°C fan), gas 6, five trays still roast at 200°C (180°C fan), gas 6. Use more trays, swap them round halfway, and expect it to take a bit longer because a crowded oven is a cooler oven.
• Cooking time. A bigger pot takes longer to come up to temperature, and a big pile of onions takes much longer to brown, but a curry won't need five times as long to simmer. Go by cues and a thermometer, not a multiplied number.
• Whole spices. Cinnamon, cardamom, cloves and bay leaves are perfume, and perfume doesn't multiply politely. I now use roughly double to triple for a five-times batch.
• Salt and chilli. Start at around three-quarters of the scaled amount, then season to taste at the end. You can always add. You cannot un-salt twenty portions of curry.
• Pan space. An overcrowded pan steams instead of browning, and one enormous pot on a domestic ring heats unevenly. Two medium pots beat one giant one almost every time.

The one we did properly

Last spring my parents had their anniversary lunch at ours: twenty-two people, mostly aunties, plus a handful of small cousins who would only eat rice and the potatoes. Same small kitchen, but this time I treated it like a project rather than a dare. (T still brings up the timeline I made in a spreadsheet, with colour coding. T brings up less often that the spreadsheet worked.)

The curry was a plain Bangladeshi chicken curry, the everyday kind with lots of onion, bone-in pieces and a loose gravy for the rice. I cooked it the day before across two pots side by side on the two good rings, chilled it overnight and reheated it on the day. Every Bangladeshi aunty already knows this, but curry tastes better the next day. The gravy settles, the spices round off, and you get to have a shower before the doorbell goes.

Not everything went to plan. I'd assumed the onions would take fifteen minutes, like they do for four. Nearly two kilos of sliced onion took closer to forty, split across two pots, and I had to be dragged away from the hob to eat my own dinner. I also forgot how much space twenty-two portions take up in a fridge. The night before the lunch, every bottle of drink we owned went out on the balcony so the curry could have the shelves.

But the food came out right. The gravy was rich without being heavy. My mum asked for the recipe, which has never happened before and may never happen again, and then told me I'd used too much ginger, which happens every time.

Chicken curry for twenty

This is what I cooked, written for two large pots (at least 8 litres each) on a normal home hob. Split every ingredient equally between them. If you own a single pot big enough and a burner strong enough to heat it evenly, you can use one, but most of us don't. Serve with plain rice (about 1.5kg of uncooked basmati for twenty people) and a big bowl of sliced cucumber and onion with lemon.

Ingredients (serves 20)

• 5kg skinless chicken thighs and drumsticks, on the bone
• 200ml neutral oil
• 3 cinnamon sticks, broken in half
• 8 green cardamom pods, lightly crushed
• 8 cloves
• 6 bay leaves
• 10 medium onions (about 1.8kg), thinly sliced
• 5 tbsp ginger paste
• 5 tbsp garlic paste
• 5 tsp ground turmeric
• 3 tbsp ground coriander
• 1½ tbsp ground cumin
• 5 tsp chilli powder, plus more to taste (three-quarters of a straight five-times scale)
• 1kg ripe tomatoes, chopped, or two 400g tins of chopped tomatoes
• 5 tsp salt to start, plus more to taste (also three-quarters)
• 1 litre water, plus up to 500ml more if needed
• 10 to 12 green chillies, slit lengthways
• 2 tsp garam masala
• A large bunch of fresh coriander, chopped

Method

1. Do the prep first, ideally the day before you serve. Slice the onions in batches in a food processor if you have one, because slicing 1.8kg by hand will make you cry for reasons that aren't only emotional.
2. Set two large pots over a medium heat and add half the oil to each. When the oil shimmers, divide the cinnamon, cardamom, cloves and bay leaves between the pots and let them sizzle for about 30 seconds.
3. Add half the onions to each pot with a pinch of the salt. Fry, stirring often and scraping the bottom, for 30 to 40 minutes, until soft and a deep golden brown. Turn the heat down if they catch. This stage is slow at this size, so don't rush it.
4. Stir half the ginger and garlic pastes into each pot and fry for 2 minutes, until the raw smell has gone.
5. Add half the turmeric, coriander, cumin and chilli powder to each pot with a splash of water so the spices don't burn. Stir for 1 to 2 minutes.
6. Add half the tomatoes to each pot. Cook for 10 to 15 minutes, stirring, until they have broken down into a thick paste and the oil starts to show at the edges.
7. Divide the chicken between the pots and turn it to coat in the masala. Cook uncovered for 10 to 15 minutes, stirring now and then, until the outside of the chicken is no longer pink and the masala is clinging to it.
8. Add 500ml water and half of the remaining salt to each pot. Bring to a simmer, cover, and cook gently for 35 to 45 minutes, stirring from the bottom every 10 minutes. Add more water a splash at a time if it looks dry.
9. Check the chicken is cooked: the thickest pieces should reach 75°C next to the bone on a food thermometer, with no pink meat and clear juices. Big pots take longer, so check several pieces from each pot, not just one from the top.
10. Add the green chillies and garam masala and simmer, uncovered, for 5 more minutes. Taste, then add more salt and chilli powder little by little if it needs it. Scatter with coriander to serve.

Making it ahead, safely

This is the boring bit, and it's the bit that matters most with a crowd. A big pot of curry holds its heat for hours, which is lovely on the table and risky in the kitchen, because it spends a long time at the warm temperatures bacteria like.

• Cool it quickly. Don't leave a full pot on the hob overnight. Divide the curry into shallow containers so it cools faster, and get it into the fridge within two hours. Sooner is better.
• Make room in the fridge before you start cooking, not at eleven at night with a curry going cold on the hob. See above, re: the balcony.
• Eat it within two days of cooking.
• Reheat it only once. Bring it back to a simmer, stirring well, until it's steaming hot all the way through, including the pieces at the bottom.
• Once it's out for serving, keep it hot on a low heat. Anything that has sat at room temperature for more than two hours should go in the bin, not back in the fridge.
• Rice needs extra care. Cook it on the day, serve it hot, and cool any leftovers within an hour. Keep them in the fridge, eat them within a day and reheat only once.

What I'd do differently next time

I'd start the onions earlier, or fry them the day before that and keep them in the fridge, because nothing else can start until they're done. I'd borrow a second large pot well before the weekend, rather than at nine at night from a neighbour who now thinks I'm opening a restaurant. And I'd plan the rice in batches from the start, because our biggest saucepan can't take more than about 500g of uncooked basmati before the bottom layer turns to stodge.

What I wouldn't change is the three-quarters rule. At the end, the curry needed about another teaspoon of salt and no extra chilli at all. If I'd gone in with the full scaled amount, it would have been too salty by the time the gravy reduced, and there's no fixing that with twenty-two people in the next room.

T, for what it's worth, thought it needed more chilli. T always thinks it needs more chilli. There were children present.

Cook it with Jan

Want to make bangladeshi chicken curry tonight? Jan will scale it for your crowd and walk you through every step.

Let's cook!

• Recipe scaling
• Cooking for a crowd
• Technique
• Bangladeshi chicken curry
• Make-ahead
• Food safety