Oysters warmed in a hot oven and finished with frozen shavings of buckwheat butter are one of the fastest impressive starters in the French repertoire. This is a Maison Bordier recipe for four. The oysters go into the oven just long enough to lose their chill, then get covered in curls of Bordier Buckwheat Butter that melt on the way to the table. Lime zest cuts the richness and dill keeps it bright. Cooking runs 12 minutes, and the only real work happens in the freezer beforehand.
At a glance
- Difficulty: Medium
- Serves: 4
- Active time: About 15 minutes, plus freezer time for the butter shavings
- Cook: 10 to 12 minutes
- Key ingredient: 80 g Bordier Buckwheat Butter
Why this works
Buckwheat, or sarrasin, is the grain Brittany built its kitchen on. Jean-Yves Bordier added it to butter in 2016 at the suggestion of a Breton chef, toasting the groats so they give up a dark, nutty, faintly smoky flavor. Two Breton staples in one block. Against an oyster, which is briny and mineral and a little sweet, that toastiness does what a buckwheat crepe does under smoked fish: it grounds the whole thing.
The technique here is the clever part. Instead of melting butter into a sauce, you shave it cold and let the oyster's own residual heat do the work. Frozen curls hold their shape long enough to reach the table, then collapse slowly over the warm shell, so each bite gets butter at a slightly different stage. Melt the butter in a pan first and you lose that, along with some of the roasted buckwheat aroma, which is volatile and does not survive hard heat.
Ingredients
Four servings. Flat oysters (belons, or any large flat variety your fishmonger has) hold the heat better than cupped ones.
| Ingredient | Metric | US |
|---|---|---|
| Churned Buckwheat Butter by Bordier | 80 g | About 2.8 oz, a little under one 4.4 oz block |
| Large flat oysters | 4 | 4 |
| Organic lime | 1 | 1 |
| Dill leaves | A few | A few |
Method
Step 1: Shave the butter and freeze it
Line a large flat plate with plastic wrap and put it in the freezer to chill. Using a vegetable peeler, cut 40 shavings from the block of Bordier Buckwheat Butter and lay them on the chilled plate. If the butter starts softening under your hand and the shavings tear rather than curl, put the block back in the freezer for a few minutes and pick up where you left off. Keep the finished shavings on their plate in the freezer until you need them.
Step 2: Warm the oysters
Heat the oven to 200°C (400°F). Shuck the oysters, pour off the first water and cut the muscle free from the shell. Set them on a tray and give them 10 to 12 minutes at 200°C (400°F). You are looking for lukewarm, not cooked. Push them past that and they turn rubbery.
Step 3: Finish and serve
Take the oysters out and cover each one with shavings of buckwheat butter straight from the freezer. Add a grating of lime zest and a few dill leaves. Serve right away, while the butter is still collapsing.
Tips from our kitchen
- Freeze the block, not just the plate. A block at refrigerator temperature will smear under a peeler. Twenty minutes in the freezer firms it enough to throw clean curls, and the shavings then hold their shape on the plate.
- Ten shavings per oyster. Forty shavings across four oysters is the ratio Bordier intends, and it is more butter than it sounds. Do not thin it out. The point of the dish is that the oyster arrives half hidden under butter.
- Steady the shells with rock salt. A bed of coarse salt or crumpled foil on the baking tray keeps the oysters level so the liquor does not run out in the oven. Losing that liquor is what makes oysters dry.
- Watch the edges, not the clock. Ovens vary. The oyster is ready when the edges just begin to ruffle and the flesh is warm to a fingertip. If it has plumped and firmed, you have gone too far.
- Zest the lime last. Citrus oils fade within a minute or two of grating. Zest directly over the plated oysters so the aroma lands where it belongs.
- No flat oysters? Use cupped. Cupped Pacific or Kumamoto oysters work, but they hold more liquor and warm faster. Start checking at 8 minutes.
How to serve it
Serve these as a first course, one oyster per person, with brown bread and a glass of dry cider or Muscadet. They are also a good opening for a shellfish dinner, since the buckwheat and dill set up whatever comes next without repeating it. If you want to keep the butter theme running through the meal, our guide to Bordier butter covers which flavors belong with seafood and which are better saved for dessert.
Where to Buy Bordier Buckwheat 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 Buckwheat Butter by Bordier (4.4 oz): roasted Breton buckwheat folded into hand-churned butter, nutty and faintly smoky.
For the rest of the range, including seaweed, salted and Espelette pepper, browse the Maison Bordier collection.
Frequently asked questions
How much butter do I need to buy for this recipe?
The recipe calls for 80 g. A Bordier block is 125 g, or 4.4 oz, so one block covers it with about a third left over. If you plan to serve the dish twice, buy two.
Can I substitute another butter?
Bordier Seaweed Butter is the closest match in spirit, iodised and Breton, and it works beautifully on a warm oyster. Salted butter with a little toasted buckwheat crushed over the top is a rougher approximation. Neither gives you the roasted-grain depth of the buckwheat butter itself.
How should I store the butter?
Keep it wrapped in the refrigerator and use it within the date on the pack. It takes on other smells easily, so keep it away from anything strongly scented. For longer storage, freeze the block whole and thaw it in the refrigerator overnight.
Does the butter need to be refrigerated?
Yes. Bordier butter is a fresh, hand-churned product and ships cold. Move it to the refrigerator as soon as it arrives.
Can I shave the butter in advance?
Yes. The shavings hold well on their plastic-lined plate in the freezer for several hours, which makes this a practical dish for a dinner party. Cover the plate loosely so the curls do not pick up freezer odours.
Is the lime or the lemon correct?
Maison Bordier lists one organic lime in the ingredients, and that is what we have followed. Lemon zest is a reasonable swap if lime is what you have, though lime is sharper against the buckwheat.
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
- La Brújula Spanish Conservas
Recipe and photograph adapted from Maison Bordier, with thanks. The French Pantry is an authorized US retailer of Bordier butter.