Broccoli Cheddar Soup
Broccoli Cheddar Soup is the American soup-counter classic: a butter-and-flour base loosened with broth and milk, 500 g of broccoli simmered until it collapses, and 250 g of sharp cheddar stirred in at the end for a glossy, savoury finish. This version keeps the pot below a boil once the cheese goes in, which is the whole difference between a silky soup and a grainy one, and grates a carrot into the base for colour and a little sweetness. Allow about 15 minutes of prep and 30 minutes of cooking, most of it hands-off simmering.
- Prep
- 15 min
- Cook
- 30 min
- Total
- 45 min
- Serves
- 4
Ingredients
What you’ll need — tap to tick off as you go
- 4 tbsp
- 4 tbsp
- 500 ml
- 500 ml
- 500 g
- 250 g
- 1 tsp
- ½ tsp
- ½ tsp
Process
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Melt the 4 tbsp butter in a large heavy pot over medium heat. Add the 1 finely chopped onion and cook for about 5 minutes, stirring now and then, until it is soft and translucent but not browned; browned onion darkens the pale colour of the soup and adds a sweetness that fights the broccoli.
Sprinkle the 4 tbsp flour over the onions and stir constantly for 1 to 2 minutes to form a roux, keeping the heat at medium. Stop as soon as the paste looks smooth, smells like cooked pastry rather than raw flour, and is still pale; letting it brown would deepen and darken the soup instead of thickening it quietly.
Whisk in the 500 ml chicken broth gradually, in a steady stream, so the roux disperses before more liquid lands on it, then whisk in the 500 ml milk the same way. Bring the pot to a bare simmer, whisking the corners and base, until the liquid is smooth and lightly thickened.
Add the 500 g broccoli, the 1 grated carrot if using, 1 tsp salt, 0.5 tsp black pepper and 0.5 tsp garlic powder. Simmer for 15 to 20 minutes, stirring the bottom of the pot now and then, until the stems and florets pierce easily with a small knife and are soft enough to crush against the side of the pot; keep it below a hard boil so the milk does not scorch.
Reduce the heat to low and let the soup settle until it is steaming rather than bubbling, then add the 250 g shredded cheddar one handful at a time, stirring until each addition has melted before the next goes in. Do not boil after the cheese goes in: high heat tightens the cheese proteins and turns the soup grainy.
Taste and adjust the seasoning: add a little more salt only if the soup needs it, because the cheddar brings salt of its own, and a final grind of black pepper if the flavour reads flat rather than bright. Ladle into warmed bowls and serve hot, while the emulsion is still glossy.
Why this recipe works
The roux is the hidden stabiliser: as the flour cooks in butter, its starch swells and thickens the water phase of the broth and milk, and that body physically keeps melted cheddar fat from gathering back into a greasy slick. Cheddar's protein matrix collapses around 65°C into a smooth melt, and it stays smooth only while the pot is kept below a boil; boil it and the proteins tighten into clumps that leak fat, which is exactly the grainy, stringy texture this soup is famous for getting wrong. Simmering the broccoli in the seasoned base also thickens the pot as soft pieces crush into the liquid.
Equipment
- Large heavy-bottomed pot or Dutch oven, 3 to 4 litres
- Whisk
- Wooden spoon or heatproof spatula
- Box grater
- Chef's knife and cutting board
- Measuring jug, cups and spoons
- Ladle
- Potato masher or immersion blender (optional, for a thicker soup)
Kitchen notes
Kitchen notes
- Grate the cheddar on the coarse holes of a box grater and let it sit out for 15 to 20 minutes first; room-temperature shreds melt faster and more evenly, while cold cheese drags the pot temperature down and clumps before it melts.
- If you want insurance against graininess, stir a small piece of American-style processed cheese in with the first handful of cheddar; its emulsifying salts hold fat and water together, which is the same trick that keeps packaged cheese sauce smooth.
- Mash a third of the broccoli against the side of the pot with a potato masher before the cheese goes in; the crushed florets thicken the soup without extra flour, and the pieces left whole keep some texture.
- Keep a cup of hot broth or milk covered at the side of the stove and use it to loosen the soup at the table; a cheese soup tightens as it cools and as it stands, and thinning with hot liquid keeps the texture even.
- Hold back some of the 1 tsp salt in step 4 and add it at the end instead; cheddar varies in saltiness from block to block, and the only way to know where the soup lands is to taste it after the cheese has melted.
Common mistakes
- Grainy, stringy soup: the pot was boiling when the cheese went in, or it boiled afterwards, so the cheddar proteins tightened and the fat separated. Keep the heat low, let the soup settle to a steam before adding the 250 g of cheddar in handfuls, and never let it boil once the cheese is in.
- Lumps in the base: the flour was not cooked through as a roux, or the broth and milk went in all at once. Stir the roux for a full 1 to 2 minutes first, then add the 500 ml broth and 500 ml milk in slow streams, whisking the corners of the pot as you go.
- A scorched, slightly bitter base: milk catches on the bottom of a thin pot. Use a heavy pot, keep the heat low enough that the soup shivers rather than boils, and drag a spoon across the bottom every few minutes during the 15 to 20 minutes the broccoli cooks.
- Thin, watery soup: too little of the broccoli was crushed into the base, or the flour was shaken out short. Let some florets break against the side of the pot as they cook, and mash a ladleful or two before the cheese goes in instead of reaching for more flour at the end.
- Flat, dull flavour: the soup was under-salted before the cheese went in, or a milder cheddar was used where sharp was called for. Season the base lightly in step 4, use the full 250 g of sharp cheddar, and adjust with salt and black pepper after the cheese has melted.
- Mushy broccoli and dull colour: florets were cut unevenly, so the small ones collapse while the stems stay firm. Cut pieces to roughly the same size, about 2 to 3 cm, and start testing with a knife at 15 minutes.
Serving suggestions
- Ladle into warmed bowls and eat within 10 to 15 minutes of the cheese going in, while the emulsion is still glossy; the soup tightens and the broccoli keeps softening as it sits.
- A crusty baguette, sourdough or a soft bread roll is the classic side, and a bread bowl turns it into a full lunch.
- A sharp green salad with a mustard vinaigrette cuts the richness and resets the palate between spoonfuls.
- Finish each bowl with a grind of black pepper and a pinch of extra cheddar, and keep portions to about 375 ml if the soup is a first course.
Variations
- Blended version: puree the soup with an immersion blender before the cheese goes in, or blend only half of it so some florets stay whole, for a velvety texture in the same flavour profile.
- Spiced version: add a pinch of cayenne or a few dashes of hot sauce with the garlic powder; the heat plays well with cheddar and cuts the richness.
- Roasted broccoli version: roast some of the florets at 220°C for 10 to 15 minutes until the edges char, simmer the rest of the broccoli as written, and fold the roasted florets in with the cheese so the bowl gets both soft and toasty pieces.
Refrigerator
- RefrigeratorCool the soup within 2 hours of cooking, then refrigerate it in an airtight container for up to 3 days. It thickens as it sits and the broccoli softens further; a splash of milk or broth when you reheat it brings it back to a ladleable consistency.
- ReheatingReheat gently on the stovetop over low heat, stirring often, until the soup is steaming hot all the way through; 74°C (165°F) is the USDA reheat target for leftovers. Add a splash of milk or broth if it has thickened, and keep it off a rolling boil so the cheddar does not turn grainy.
- FreezingFreezes acceptably for up to 2 months in a freezer-safe container; cool it completely first and leave 2 cm of headroom. Dairy soups can separate slightly on thawing, so thaw overnight in the fridge and reheat gently, whisking in a splash of milk, and expect a slightly softer texture.
- Make aheadYes, and it is arguably better the next day. Make the base up to 2 days ahead: cook through the broccoli stage, cool, and refrigerate, then reheat gently and stir the cheddar in just before serving. A fully made soup also reheats well; thin it with milk or broth as needed.
Updated:
How this recipe was developed
- USDA FSIS leftovers guidance (refrigerate within 2 hours; 3 to 4 days in the fridge; reheat to 74°C / 165°F; frozen leftovers 3 to 4 months)
- Serious Eats — J. Kenji López-Alt on broccoli cheese soup and broken cheese sauces: the roux starch stabilises the emulsion, and cheddar's protein matrix collapses around 65°C (quoting Harold McGee, On Food and Cooking)
- America's Test Kitchen / Cook's Illustrated on sodium citrate and melting salts: why long-aged cheddar melts coarsely and how emulsifying salts keep the emulsion smooth
- BBC Good Food — how to cook broccoli: the doneness cue is a knife that pierces the stem easily, and softer broccoli suits soups
Editorial references are kept internally for verification. This page makes no claim of external certification or professional testing.
FAQ
The questions we get asked most
Why did my broccoli cheddar soup turn grainy?
It is almost always heat or cheese choice: cheddar proteins tighten and squeeze out fat when the pot boils, and pre-shredded cheese carries starch that fights melting. Grate the 250 g yourself from a block, let the soup settle to a steam before the cheese goes in, add it by handfuls, and keep the heat low afterwards. If it is already grainy, blending a ladleful smooth and stirring it back will rebuild some creaminess.
Can I use frozen broccoli?
Yes, and it saves time: add it frozen, straight from the bag, without thawing, and give it 2 to 3 minutes longer because frozen broccoli releases extra water. The florets come out softer than fresh, which suits a soup that is meant to be spooned.
How do I make the soup thicker?
Mash a third of the cooked broccoli against the side of the pot, or blend a ladleful and return it, before the cheese goes in; the crushed florets thicken the base without extra flour. Simmering uncovered for a few minutes also drives off water. Adding raw flour at the end only tastes of raw flour and clumps.
Can I make it ahead of time?
Yes. Cook the base through the broccoli stage up to 2 days ahead, cool it quickly and refrigerate, then reheat gently and stir the cheddar in just before serving. A fully assembled soup reheats well for a day or two, though it will be thicker and the broccoli softer each time.
Can I use pre-shredded cheddar?
It is the most common reason a home-made version turns grainy: the starch and cellulose that keep shreds loose in the bag also keep them from melting smoothly into the soup. Grate 250 g from a block for the best texture; if pre-shredded is all you have, keep the heat noticeably lower and expect a slightly coarser result.
How long does the soup keep, and what is the best way to reheat it?
Up to 3 days in an airtight container in the fridge. Reheat on the stovetop over low heat, stirring, until it is steaming hot all through, about 74°C, and thin it with a splash of milk or broth; avoid a hard boil, which breaks the cheese emulsion and turns the soup grainy.
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