Broccoli soup
One rule for keeping it green: no lid, and not a minute over eight.
Soups · International · Under 30 minutes · One pot · Seasonal
- Preparation
- 10 min
- Cooking
- 20 min
- Difficulty
- Needs attention
- Cost
- Cheap
- Season
- Autumn, Winter
Broccoli’s green is chlorophyll, and chlorophyll meeting acid loses its magnesium atom and becomes pheophytin — olive drab. Cooking broccoli releases the acids in its own cells, and under a lid those acids condense and come back to kill the colour. Leaving the lid off lets them go. It is one of the few places where a rule of chemistry is directly visible on the plate.
Method
- Break the broccoli into florets and peel and dice the thick stalk: the stalk is not waste, it is the sweetest part.
- Dice the potato small so it cooks in twelve minutes.
You will need: A pan · A stick blender
-
Soften the onion in the butter for five minutes, add the potato and water and boil twelve minutes.
Look for The potato should crush easily under a fork.
Why The potato is the body of the soup: its starch goes into the water and builds the texture, which is why no flour or cream is needed.Starch gelatinised The granules soaked up water, swelled and burst into a network. It has thickened, and it will firm further as it cools. no way back
-
Add the broccoli and cook seven minutes with the LID OFF. Not a minute longer.
Look for The broccoli should go bright green and still meet slight resistance on a fork.
Why Broccoli’s own acids leave with the steam, and a lid sends them back, turning chlorophyll into pheophytin and the colour olive. The time is part of the same rule: past ten minutes it yellows anyway.If it went wrong
Once the colour has turned it does not come back. Finish that batch with plenty of pepper and a spoon of butter and eat it; for the colour, next time take the lid off and time it.
Starch gelatinised The granules soaked up water, swelled and burst into a network. It has thickened, and it will firm further as it cools. no way back
-
Blend it smooth, add the milk, salt and pepper and warm it two minutes without boiling.
Look for It should come out velvety; more than thirty seconds of blending overworks the potato starch and turns it gluey.
Why The milk goes in last and unboiled: cooked long against broccoli’s sulphur compounds it can curdle, and it develops a heavy smell.Starch gelatinised The granules soaked up water, swelled and burst into a network. It has thickened, and it will firm further as it cools. no way back
Salt · 0.34% Low. Everything reads flat and nothing steps forward.
This recipe was run through the engine step by step — what goes in when, and at what temperature and for how long. The reactions above come from that run.
peak 98 °C · 26 minutes · engine 1.0.0 · confidence low
After the heat goes off
Hot, with grated kaşar or a scatter of toasted almonds. Nothing sour: lemon kills the colour too.
Two days in the fridge, though the colour turns noticeably by the second. For the colour it wants eating the same day.
Low flame, no boiling. Every reheating takes a little more of the colour.
Not for the freezer: the milk separates and the colour goes completely.
Reduced it becomes a pasta sauce, or mashed with a boiled egg it becomes a sandwich filling.
From eight months for a baby: unsalted, without the milk and blended completely smooth. For 12–36 months lift their share before the salt. Broccoli’s sulphur smell is heavy going for some children; if so raise the potato and cut the broccoli — a rejected bowl is an uneaten bowl.
- Broccoli → Cauliflower The same recipe works with cauliflower and the colour problem disappears: you can use a lid, and the time goes up to ten minutes.
- Milk → Oat milk Oat milk is the lactose-free answer and cannot curdle.
- Boiling & poaching The method this recipe rests on
- Broccoli What it does in heat, water and acid
- Milk What it does in heat, water and acid
- Potato What it does in heat, water and acid
- Vegetable soup Similar method, or something that sits on the same table
- Pumpkin soup Similar method, or something that sits on the same table
- Mushroom soup Similar method, or something that sits on the same table
- Under 30 minutes Other recipes that answer the same need
- One pot Other recipes that answer the same need
- Seasonal Other recipes that answer the same need
What it tastes like
No axis sits clearly above the average: a balanced recipe.
This profile is computed rather than measured: the role-weighted average of its ingredients’ taste vectors, shifted by what the cooking does. The thin line is the database average on that axis.
Closest in taste
Not hand-picked: ranked by distance across the eight taste axes.

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