Jerusalem artichokes taste faintly of hazelnut and globe artichoke, and Roscoff onion butter is the thing that pulls both forward. This is a proper French veloute: the aromatics are sweated in butter, the vegetables cook covered in their own steam before any water goes in, and cream arrives only at the end. Prawns get one minute in a scorching pan and finish off the heat. It serves two, it is genuinely easy, and it takes about 40 minutes.
At a glance
- Difficulty: Easy
- Serves: 2
- Active time: About 15 minutes
- Cook: 10 minutes covered, then 20 minutes at a boil, plus 3 minutes for the prawns. Bordier gives no total time.
- Key ingredient: 20 g (4 tsp) Bordier Roscoff Onion Butter
Why this works
Twenty grams of butter is a small amount to carry a whole soup, and it works because of where it goes in. Bordier's Roscoff onion butter, made since 2016 after Jean-Yves Bordier met the Johnnies of Roscoff who once sold their pink onions door to door across Britain, uses the mild AOP Roscoff onion. Sweating the shallots in it at the very start puts that sweetness underneath everything that follows, rather than laying it on top. Jerusalem artichokes are sweet and nutty in a way that plain onion would fight; the Roscoff, which is gentler and almost caramel, agrees with them instead.
The structure of the cooking is what makes it silky. Ten minutes covered with no liquid lets the artichokes give up their own moisture and soften in butter, which concentrates them. Only then does water go in, and only enough to cover, so the soup is never diluted. Cream comes in after blending, off the boil, where it enriches without splitting. The prawns follow the same logic in miniature: one minute of real heat for colour, then two minutes in the switched-off pan, which cooks them through by residual heat instead of tightening them into rubber.
Ingredients
Everything here is either sweated, boiled or seared. Have the chives chopped before you start, since the last three steps happen quickly.
| Ingredient | Metric | US |
|---|---|---|
| Jerusalem artichokes, medium | 5 | 5 |
| Bordier Roscoff Onion Butter | 20 g | 4 tsp |
| Small potato | 1 | 1 |
| Shrimp or prawns, medium | 6 | 6 |
| Whipping or single cream | 20 cl | 6 3/4 fl oz (a scant cup) |
| Shallots | 2 | 2 |
| Olive oil | 5 cl | 1/4 cup |
| Chives | To finish | To finish |
| Pepper and fleur de sel | To taste | To taste |
Method
Step 1: Sweat, simmer and blend the veloute
Peel and mince the shallots. Peel the Jerusalem artichokes and trim them into even shapes. Sweat the shallots in the onion butter in a pan. Add the artichokes, cover, and cook for 10 minutes. Pour in enough water to cover, then boil for a further 20 minutes and blend. Stir in the cream and check the seasoning.
Step 2: Sear the prawns and plate
Heat the olive oil in a very hot pan. Peel the prawns and brown them for 1 minute. Turn off the heat and leave them in the hot pan for another 2 minutes. Spoon the soup into deep plates and arrange the prawns on top. Finish with freshly ground pepper, a pinch of fleur de sel, a dash of olive oil and finely minced chives.
Tips from our kitchen
- The potato is listed but never mentioned again. Bordier's ingredient list includes one small potato and the method never calls for it. Our reading, and it is our guidance rather than theirs, is that it goes in peeled and chopped alongside the artichokes in step one. A potato is standard in a veloute of this kind: its starch gives body so the soup holds together without more cream.
- Peel the artichokes into acidulated water. They oxidise within minutes and turn the finished soup grey rather than ivory. A bowl of water with a squeeze of lemon while you work solves it entirely. A small sharp knife beats a peeler on their knobbly shape.
- Cover to the top of the vegetables, not above. Bordier says water to cover, and that is precise instruction, not vagueness. Excess water is the usual reason a veloute tastes thin, and you cannot boil it back out without overcooking the artichokes.
- Add the cream off the boil. Blend first, drop the heat, then stir the cream in. Boiling cream in a blended vegetable soup can split it, and you lose the clean sheen that gives a veloute its name.
- The pan must be genuinely hot before the prawns go in. You want the oil shimmering. One minute is only enough to colour them if the surface is hot on contact, and the two minutes off the heat afterwards is what actually cooks them through. Prawns that go into a warm pan will stew and turn grey.
- Finish at the table, not in the kitchen. Fleur de sel loses its point once it dissolves. Add the salt, the pepper and the oil as the plates go down so the crystals still crunch.
How to serve it
This is a first course, and it wants shallow, wide bowls so the prawns sit visibly on the surface rather than sinking. A little toasted bread on the side is enough. The finishing salt and pepper matter more than they sound here, since the soup itself is soft and sweet and needs points of contrast on top: our Terre Exotique guide is a good starting point if you want to go beyond ordinary black pepper for the final grind.
Where to buy Bordier Roscoff Onion Butter in the US
The French Pantry ships Bordier butter across the United States in insulated overnight packaging, straight from the workshop in Brittany.
- Churned Roscoff Onion Butter by Bordier (4.4 oz): pink AOP Roscoff onion folded into hand-churned Breton butter, mild and gently sweet, and the base note under this whole soup.
For the rest of the range, browse the Maison Bordier collection.
Frequently asked questions
How much Bordier Roscoff Onion Butter do I need for this recipe?
Only 20 g. A Bordier block is 125 g (4.4 oz), so a single block makes this soup six times over. Use the rest on toast or stir a knob into mashed potato.
Can I substitute another butter?
Jerusalem artichokes are sweet, so a savoury butter suits them. Wild Garlic and Kampot Pepper Butter is the closest alternative in character. Salted Butter works too, in which case sweat an extra shallot to make up the onion note.
Can I use parsnips instead of Jerusalem artichokes?
Parsnips are the usual stand-in and the method is unchanged, though they are sweeter and less nutty. Jerusalem artichokes are worth seeking out for their faint artichoke bitterness, which is what keeps the soup from being one-note.
How do I store the butter once it is open?
Keep it wrapped in its paper inside an airtight container, in the coldest part of the fridge, for about two weeks. It absorbs other flavours quickly. It freezes for up to three months.
Does Bordier butter need refrigeration?
Yes. Bordier butter is a fresh, hand-churned product and ships cold in insulated overnight packaging. Move it into the fridge as soon as it arrives.
Can I make the soup ahead?
The blended base keeps two days in the fridge and reheats gently without trouble. Add the cream when you reheat rather than before, and cook the prawns to order.
Related reading
- Bordier Butter: What It Is, Why Chefs Love It, and How to Use It
- How to Choose Your French Butter: A Buyer's Guide
- Terre Exotique
Recipe and photograph adapted from Maison Bordier, with thanks. The French Pantry is an authorized US retailer of Bordier butter.