Oily fish and raspberry sounds like a stretch until you taste it, and then it is obvious. Mackerel is rich and assertive, the kind of fish that wants acid alongside it, and Bordier's Raspberry Butter delivers that acid inside the fat used to cook it. Everything here goes on a flat griddle: the eggplant, the spring onions, the mackerel. The tomatoes are dried slowly beforehand, and a quick pan sauce of raspberries and raspberry vinegar pulls the plate together.
At a glance
- Difficulty: Medium
- Serves: 4
- Active time: Not specified by Maison Bordier. The griddle work is quick once the tomatoes are done
- Cook: No total time given. The tomatoes alone need 2 hours at 80°C (175°F)
- Key ingredient: 250 g Bordier Raspberry Butter
Why this works
Bordier's Raspberry Butter came out of a suggestion from a pastry chef friend in 2006, and it is built on salted butter rather than unsalted. That salt is the reason it works in savoury cooking at all. The raspberry brings tartness and a little fruit sugar, the salt keeps it from reading as dessert, and together they do the job a squeeze of lemon or a splash of vinegar would normally do next to mackerel. The difference is that the acid is suspended in the cooking fat, so it seasons the fish from the pan rather than being added at the table.
The rest of the recipe is about concentration. Tomatoes held at 80°C for two hours are not roasting, they are drying: the water leaves slowly, the sugars stay put, and what is left is intensely tomato. Cooking a la plancha, on a flat griddle rather than over bars, does something similar to the eggplant and onions, giving broad contact with hot metal and a proper browned surface. The final sauce is a classic deglaze, using raspberry vinegar to lift the browned butter solids off the pan and turn them into something you can spoon.
Ingredients
Enough for four.
| Ingredient | Metric | US |
|---|---|---|
| Eggplant | 1 | 1 |
| Mackerel fillets | 2 | 2 |
| Bordier Raspberry Butter | 250 g | 8.8 oz, exactly 2 blocks |
| Basil | 1 bunch | 1 bunch |
| Spring onions | 4 | 4 scallions |
| Raspberries | 12 | 12 |
| Tomatoes | 3 | 3 |
| Raspberry vinegar | to taste | to taste |
Method
Step 1: Cut the eggplant and dry the tomatoes
Slice the eggplant lengthwise and shape the slices into strips. Peel and core the tomatoes, cut them into quarters, and dry them in raspberry butter at 80°C (175°F) for 2 hours.
Step 2: Griddle the vegetables and the fish
Cook the eggplant and the spring onions a la plancha in raspberry butter, on a flat griddle or heavy pan. Cook the mackerel fillets a la plancha as well.
Step 3: Make the sauce and plate it
For the sauce, brown the raspberries in raspberry butter, then deglaze with raspberry vinegar and add basil leaves. Present everything bruschetta-style.
Tips from our kitchen
- Bordier lists no bread. "Bruschetta-style" here describes how the plate is built, layered and open-faced, rather than a bread base in the ingredient list. If you want to serve it on toast, choose the bread yourself and grill it in a little of the same butter.
- Skin side down first for the mackerel. Get the griddle properly hot, lay the fillets skin down, and leave them alone until the skin releases on its own. Moving the fish early is how the skin tears and sticks.
- 80°C is a drying temperature, not a roasting one. If your oven will not go that low, use its lowest setting and prop the door open a crack with a wooden spoon. Too much heat and the tomatoes cook into a sauce instead of concentrating.
- Salt the eggplant strips and pat them dry. Eggplant is mostly water, and wet strips steam on the griddle rather than browning. Fifteen minutes under salt, then a firm blot with a towel, makes the difference.
- Watch the butter, it will brown fast. Raspberry butter contains fruit sugar as well as milk solids, so it colors quicker than plain butter and can go bitter. Work on medium heat and add it in stages rather than all at once.
- Deglaze off the heat. Pull the pan aside before the vinegar goes in, or it hits the hot surface and evaporates before it can lift anything. The basil goes in last, off the heat, so it stays green.
How to serve it
Serve it warm rather than hot, as a first course or a light summer lunch for four. The dried tomatoes and the raspberry sauce both taste better a few degrees below piping, and mackerel firms up unpleasantly if it sits under heat. A dry white with some acidity of its own works well alongside. If you are curious about the other savoury Bordier blocks, seaweed and Roscoff onion in particular, the French churned butter collection is a good place to compare them.
Where to buy Bordier Raspberry 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 Seasonal Raspberry Butter by Bordier (4.4 oz): salted hand-churned butter set against tangy raspberry, created in 2006 at the suggestion of a pastry chef friend.
You can also browse the full Maison Bordier collection for the rest of the flavoured range and the plain salted and unsalted blocks.
Frequently asked questions
How much Bordier Raspberry Butter do I need?
Two blocks. Bordier butter comes in 125 g blocks, which is 4.4 oz each, and this recipe uses 250 g across the tomatoes, the griddling and the sauce. Buy two.
Can I use a different Bordier butter?
The raspberry is doing specific work here, supplying the acidity that cuts the oily fish, so a swap changes the dish. If you want to try another savoury block, the Seaweed butter suits mackerel well, though you will want a squeeze of lemon to replace the missing tartness. Keep the quantity at 250 g.
What does a la plancha mean?
Cooking on a flat metal griddle rather than over grill bars. A heavy cast iron pan or a flat-top griddle does the same thing at home: the point is full contact with hot metal, which browns the surface evenly.
How should I store Bordier butter?
Refrigerate it in its wrapper and use it by the date on the pack. For longer storage, wrap the block tightly and freeze it, then thaw it overnight in the refrigerator before cooking.
Does the butter need to stay refrigerated in transit?
Bordier butter is a fresh, hand-churned product and ships cold. It travels in an insulated box with coolant, and it should go into the refrigerator as soon as you unpack it.
Can any of this be prepared ahead?
The tomatoes can and should be. Two hours of drying is the long pole in this recipe, and they keep well in the refrigerator once done. Everything else is quick griddle work best done just before you serve.
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.