A croque-monsieur is only as good as the butter on the bread. Maison Bordier builds two of them here: one with white ham and Sainte-Maure de Touraine goat's cheese, the other with raw zucchini and Comte. Both are buttered with Roscoff Onion Butter, which puts the sweetness of a slow-cooked onion into the sandwich without you cooking one. Assembly takes about five minutes, and the sandwich is done a few minutes after that.
At a glance
- Difficulty: Easy
- Serves: 1 toasted sandwich per ingredient set, two versions given
- Active time: About 5 minutes per sandwich
- Cook: A few minutes, turning halfway. Bordier does not state an exact time.
- Key ingredient: Bordier Roscoff Onion Butter
Why this works
Bordier made its Roscoff Onion Butter in 2016, after meeting the Johnnies of Roscoff, the Breton growers who once bicycled strings of pink onions around Britain. The onion they grow carries an AOP, and it is sweet and low in sulfur, closer to a shallot than a yellow onion. Folded into hand-churned Breton butter, it behaves like an onion that has already been sweated for half an hour: sweet, faintly sharp, savory enough to carry a sandwich on its own.
That matters because a croque-monsieur is a sandwich with nowhere to hide. There are three or four ingredients and one cooking step. Butter the bread generously and the fat conducts heat into the crumb, so the outside crisps and browns while the cheese inside softens. The onion in the butter caramelizes slightly as that happens, which is where the flavor comes from. A plain butter gives you a grilled cheese. This gives you something with a savory backbone.
Ingredients
Bordier gives two versions, each making one sandwich. Build one, or build both and cut them in halves so everyone gets a taste of each.
Ham and goat's cheese croque
| Ingredient | Metric | US |
|---|---|---|
| Sandwich bread | 2 slices | 2 slices |
| White ham | 1 slice | 1 slice |
| Bordier Roscoff Onion Butter | 15 g | About 1 tbsp |
| Goat's cheese, Sainte-Maure de Touraine type | 3 or 4 slices | 3 or 4 slices |
Zucchini and Comte croque
| Ingredient | Metric | US |
|---|---|---|
| Sandwich bread | 2 slices | 2 slices |
| Raw zucchini | 4 slices | 4 slices |
| Bordier Roscoff Onion Butter | 15 g | About 1 tbsp |
| Comte cheese, sliced | 30 g | About 1 oz |
Method
Step 1: Build and cook the ham and goat's cheese croque
Butter the bread slices generously with the Roscoff onion butter. Lay the goat's cheese on one slice, then the slice of ham on top. Close the sandwich with the second slice of bread. Cook it in a croque-monsieur press, or under the broiler for a few minutes, turning it over halfway through so both faces brown.
Step 2: Build and cook the zucchini and Comte croque
Butter the bread the same way. Arrange the four zucchini slices on one piece of bread and lay the Comte over them. Close with the second slice. Cook in the press or under the broiler for a few minutes, again turning halfway through.
Tips from our kitchen
- Follow the ingredient list on the goat's cheese. Bordier's ingredient list asks for 3 or 4 slices, but the written step says 2. We go with the list. Three slices of a log like Sainte-Maure covers a standard slice of bread without making the sandwich sag.
- Butter both faces of the bread, inside and out. That is what "generously" means here. The butter on the inside flavors the filling as it melts, and the butter on the outside is what browns and crisps the crust. Fifteen grams is about a tablespoon, which is enough for both slices if you spread it thin.
- Let the butter come to room temperature first. Cold Bordier butter tears soft sandwich bread. Twenty minutes on the counter, or a few seconds pressed between your palms, and it spreads cleanly.
- Slice the zucchini thin, on a mandoline if you have one. It goes in raw and only has a few minutes to soften. Slices thicker than about 2 mm stay squeaky and push the cheese apart.
- Under the broiler, stay in the room. A croque goes from golden to burnt in under a minute. Set the rack about 6 inches from the element, watch for the first brown spots, then flip. In a press, close the lid gently rather than clamping it down, or the filling squeezes out the sides.
- Failure looks like a black crust over cold cheese. If that happens, your heat was too high or your bread was too thick. Drop the rack a level and give it another minute per side.
How to serve it
Cut each croque on the diagonal and serve it hot, with a sharp green salad dressed in nothing more than vinegar and oil. The onion butter is rich, and acid on the plate keeps the whole thing moving. If you are making both versions, cut them into quarters and put them out together as a lunch for four with a bottle of dry cider. For more ways to use the flavored butters beyond the sandwich, our guide to Bordier butter covers the full range.
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, sweet and savory at once.
If you want to try the rest of the range alongside it, browse the Maison Bordier collection.
Frequently asked questions
How much Roscoff onion butter do I need for this recipe?
Each sandwich takes 15 g, so both versions together take 30 g. Our blocks are 4.4 oz (125 g), which is enough for roughly eight croques. One block covers a lunch for four with butter left over.
Can I substitute a different butter?
You can, but you will be making a different sandwich. The closest swap in the range is Bordier Salted Butter, which gives you the same rich, well-browned crust without the onion. Do not substitute the goat's cheese or the Comte if you can help it, since with this few ingredients each one is doing real work.
What bread should I use?
Bordier specifies sandwich bread, meaning a soft white pain de mie with a tight crumb. A standard American white sandwich loaf works well. Avoid a rustic sourdough with big holes, because the butter and cheese run straight through it.
Does Bordier butter need to be refrigerated?
Yes. Bordier butter is a fresh, hand-churned product and ships cold. Keep it in the refrigerator and take out only what you need, letting it soften on the counter for twenty minutes before you spread it.
How long does an opened block keep?
Wrap the cut face tightly in its own paper or in parchment and keep it in the coldest part of the refrigerator. Flavored butters pick up other smells quickly, so an airtight container is better still. Use an opened block within about two weeks for the cleanest onion flavor. Unopened blocks freeze well for up to three months.
Can I make these ahead?
Assemble them up to a few hours in advance, cover, and refrigerate, then cook straight from cold and add a minute per side. Do not cook them ahead. A reheated croque never gets its crust back.
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
- Paysan Breton: The Breton Butter Guide
Recipe and photograph adapted from Maison Bordier, with thanks. The French Pantry is an authorized US retailer of Bordier butter.