Broccoli, Potato and Onion Soup
Overview
A smooth soup of broccoli, potato and onion for 4. Allow about 15 minutes of preparation, a 30-minute rest, and 20–25 minutes of cooking. The broccoli is chopped, finely blended, and left to stand before a short simmer, so myrosinase can meet glucoraphanin. Once the soup has cooled, mustard seed powder or broccoli sprouts can be stirred in.
Ingredients (4 servings)
- 500 g broccoli, florets and tender stems
- 2 tbsp (27 g) extra virgin olive oil
- 1 medium (150 g) onion
- 1 medium (150 g) leek
- 2 stalks (80 g) celery
- 1 medium (150 g) potato, cubed
- 3 cloves (9 g) garlic, crushed
- 750 ml vegetable stock
- 1 tbsp (15 ml) lemon juice
- ¼ tsp (0.575 g) black pepper
- Salt, to taste
- 1 tsp (3 g) mustard seed powder
- 40 g fresh broccoli sprouts
Nutrition calculation uses 3 g mustard seed powder. Fresh broccoli sprouts (40 g) are the alternative garnish and are not included.
Method
-
Prepare the broccoli
Wash the broccoli thoroughly. Finely chop the florets and tender stems to rupture the plant cells and bring glucoraphanin into contact with myrosinase. -
Blend the broccoli Pulse the raw broccoli in a food processor until finely blended. Avoid heating it during processing.
-
Allow the enzymatic reaction
Leave the finely blended broccoli for approximately 30 minutes at room temperature before cooking. This allows myrosinase time to convert glucoraphanin into sulforaphane. The exact optimal resting period has not been established. -
Prepare the soup base
While the broccoli rests, warm the olive oil over medium-low heat. Add the onion, leek and celery. Cook for 5–7 minutes until softened. Add the crushed garlic and cook for another minute. -
Cook the vegetables
Add the potato and vegetable stock. Simmer for 10–12 minutes until the potato is tender. Add the rested, finely blended broccoli and cook for another 4–5 minutes, until just tender. Avoid prolonged cooking to limit losses of heat-sensitive compounds. -
Blend until smooth
Remove from the heat. Carefully blend with an immersion blender until smooth and creamy. Add water or stock if needed to adjust the consistency. -
Season and finish
Stir in the lemon juice, black pepper and salt to taste. Allow the soup to cool to a comfortable serving temperature. -
Add the myrosinase-rich garnish
Once the soup has cooled below approximately 50°C, stir in 1 tsp mustard seed powder or top with 40 g fresh broccoli sprouts. Use one garnish, not both. This may promote additional conversion of remaining glucoraphanin into sulforaphane. Use sprouts from a reputable supplier and handle them carefully, as raw sprouts carry a food-safety risk.
Nutrition
Per serving, recipe serves 4. Each included ingredient is scaled from a named per-100 g composition record by edible grams. Optional ingredients are excluded. Missing analytical values are not treated as zero.
| Nutrient | Per serving |
|---|---|
| Energy | 190 kcal |
| Protein | 6.2 g |
| Carbohydrates | 27 g |
| Sugars | 6.9 g |
| Fibre | 5.9 g |
| Total fat | 7.8 g |
| Saturated fat | 1.2 g |
| Sodium | Not established |
Sodium excludes salt added to taste and is not established, because vegetable-stock sodium varies by brand.
Sodium: Vegetable stock sodium varies several-fold by brand, and salt is added to taste, so no sodium total is published.
Key vitamins and minerals
| Nutrient | Per serving | Reference intake |
|---|---|---|
| Vitamin C | 130 mg | 144% RDA |
| Vitamin K | 160 µg | 131% AI |
| Vitamin B6 | 0.52 mg | 40% RDA |
| Folate | 120 µg | 31% RDA |
| Manganese | 0.64 mg | 28% AI |
| Potassium | 780 mg | 23% AI |
| Copper | 0.20 mg | 22% RDA |
| Vitamin B5 | 1.1 mg | 22% AI |
Vitamins and minerals supplying at least 15% of an adult reference intake, plus explicitly featured design-relevant nutrients, up to eight. RDA is a recommended dietary allowance; AI is an adequate intake, used where the evidence does not support an RDA. Nutrients below the threshold are still calculated and still count towards a daily total; a featured row is not a claim that the serving supplies a complete daily dose.
Bioactive compounds
| Compound | Per serving |
|---|---|
| Sulforaphane | Preparation-dependent |
| Kaempferol | Present — quantity not established |
| Quercetin | Present — quantity not established |
| Allicin | Present |
These compounds have no recognised intake target, so quantified amounts are shown without a percentage. A presence-only entry is carried from a supported food relationship and is not converted into an invented serving amount.
Calculation details
| Ingredient | Weight used | Composition record |
|---|---|---|
| 500 g broccoli, florets and tender stems | 500 g | USDA FDC 170379 — Broccoli, raw |
| 2 tbsp (27 g) extra virgin olive oil | 27 g | USDA FDC 171413 — Oil, olive, salad or cooking |
| 1 medium (150 g) onion | 150 g | USDA FDC 170000 — Onions, raw |
| 1 medium (150 g) leek | 150 g | USDA FDC 169246 — Leeks, bulb and lower leaf-portion, raw |
| 2 stalks (80 g) celery | 80 g | USDA FDC 169988 — Celery, raw |
| 1 medium (150 g) potato, cubed | 150 g | USDA FDC 170026 — Potatoes, flesh and skin, raw |
| 3 cloves (9 g) garlic, crushed | 9 g | USDA FDC 169230 — Garlic, raw |
| 750 ml vegetable stock | 701 g | USDA FDC 171583 — Soup, vegetable broth, ready to serve |
| 1 tbsp (15 ml) lemon juice | 16 g | USDA FDC 167747 — Lemon juice, raw |
| ¼ tsp (0.575 g) black pepper | 0.57 g | USDA FDC 170931 — Spices, pepper, black |
| 1 tsp (3 g) mustard seed powder | 3 g | USDA FDC 170929 — Spices, mustard seed, ground |
Mainly from:
- Energy: Extra Virgin Olive Oil, Broccoli
- Protein: Broccoli, Potatoes
- Carbohydrates: Broccoli, Potatoes
- Sugars: Broccoli, Onions
- Fibre: Broccoli, Potatoes
- Total fat: Extra Virgin Olive Oil, Broccoli
- Saturated fat: Extra Virgin Olive Oil, Broccoli
Assumptions and exclusions:
- 2 tbsp (27 g) extra virgin olive oil: USDA SR Legacy FDC 171413 food_portion: 1 tablespoon = 13.5 g; 2 tbsp = 27 g
- 1 medium (150 g) onion: Recipe states 150 g edible weight. USDA SR Legacy FDC 170000 food_portion: large = 150 g; medium (2-1/2 in dia) = 110 g.
- 1 medium (150 g) leek: Recipe states 150 g edible weight. USDA SR Legacy FDC 169246 food_portion: 1 leek = 89 g.
- 2 stalks (80 g) celery: USDA SR Legacy FDC 169988 food_portion: 1 stalk, medium = 40 g; 2 = 80 g
- 1 medium (150 g) potato, cubed: Recipe states 150 g edible weight. USDA SR Legacy FDC 170026 food_portion: medium = 213 g; small = 170 g.
- 3 cloves (9 g) garlic, crushed: USDA SR Legacy FDC 169230 food_portion: 1 clove = 3 g; 3 cloves = 9 g
- 750 ml vegetable stock: USDA SR Legacy FDC 171583 food_portion: 1 cup = 221 g, i.e. 0.934 g/ml; 750 ml = 700.5 g.
- 1 tbsp (15 ml) lemon juice: USDA SR Legacy FDC 167747 food_portion: 1 cup = 244 g, i.e. 1.031 g/ml; 15 ml = 15.5 g.
- ¼ tsp (0.575 g) black pepper: USDA SR Legacy FDC 170931 food_portion: 1 tsp, ground = 2.3 g; ¼ tsp = 0.575 g
- 1 tsp (3 g) mustard seed powder: Recipe states 3 g. USDA SR Legacy FDC 170929 food_portion: 1 tsp = 2 g.
- Salt, to taste — added to taste, so it is not part of an exact sodium total
- 40 g fresh broccoli sprouts — alternative garnish; the default calculation uses 3 g mustard seed powder
- Per-serving figures divide the raw edible ingredients across 4 servings of the whole pot. The cooked yield was not weighed, so these are not amounts per 100 g of finished soup.
Brain Health Notes
- Chopping the broccoli, and leaving it at room temperature, lets myrosinase meet glucoraphanin before the pot is heated. Sulforaphane is the compound formed by that meeting.
- The broccoli then cooks for only 4–5 minutes. A long boil leaves glucoraphanin in the pot while the plant enzyme is no longer active.
- Mustard seed powder or raw broccoli sprouts go in after the soup is below about 50°C, so the added enzyme is not heated through.
- The finished bowl is ordinary soup. Its sulforaphane depends on this preparation, the broccoli used, and the garnish. See broccoli for the cooked-broccoli comparison that guided the method.
Explore the foods and substances
Show 7 foods and their substances
Broccoli
Cruciferous vegetable rich in sulforaphane, folate, and glutathione precursors
Substances: Choline, Iron, Kaempferol, Magnesium, Manganese, Phosphorus (Phosphate), Potassium, Sulforaphane, Vitamin B1 (Thiamine), Vitamin B2 (Riboflavin), Vitamin B5 (Pantothenic Acid), Vitamin B6 (Pyridoxine → PLP), Vitamin B9 (Folate), Vitamin C (Ascorbate), Vitamin K (Phylloquinone), Zinc
Broccoli Sprouts
Young broccoli sprouts valued for glucoraphanin and sulforaphane potential, vitamin C, and Nrf2-supportive phytochemistry
Substances: Calcium, Glucoraphanin, Iron, Magnesium, Potassium, Sulforaphane, Vitamin B6 (Pyridoxine → PLP), Vitamin B9 (Folate), Vitamin C (Ascorbate)
Extra Virgin Olive Oil
Polyphenol-rich oil with hydroxytyrosol and anti-inflammatory properties
Substances: Hydroxytyrosol (Olive Polyphenol), Oleacein, Oleocanthal, Tyrosol
Onions
Inulin prebiotic, quercetin, and glutathione precursors
Substances: Kaempferol, Quercetin (and Isoquercetin), Vitamin C (Ascorbate)
Potatoes
Starchy vegetable providing resistant starch when cooled
Substances: Potassium, Vitamin B6 (Pyridoxine → PLP), Vitamin C (Ascorbate)