Have you ever had a croque monsieur, that delightful sandwich made with ham and Gruyère cheese and filled and topped with a creamy béchamel? If so, you know how tasty it is! We shared the croque madame, a version of the croque monsieur that is perfect for breakfast. One of the things that makes these sandwiches so unique is the sauce that goes inside and on top. As such, I wanted to share this wonderful croque madame sauce with you because it deserves its own post!
Traditionally, both sandwiches take a béchamel (or white sauce), which is made with butter, flour and milk. However, this sauce has added cheese making it a mornay (or cheese sauce). Mornay is basically béchamel with added cheese, typically Gruyère, but we are going with the less expensive and more readily available Swiss cheese. If this sounds intriguing to you, read on to learn how easy it is to make and how delicious it tastes!
- Unsalted butter (2 tablespoons). Adds flavor and helps to thicken the sauce. You can also use salted butter. If you do, you won't need to add as much salt later.
- All-purpose flour (2 tablespoons). This is used to thicken the sauce.
- Warmed milk (1 cup). Be sure to warm the milk first. Warmed milk will prevent the butter from cooling down and solidifying. Making sure the milk is warm first will keep the sauce nice and smooth.
- Shredded Swiss cheese (¾ cup). You can also use Gruyère cheese, but it is more expensive than Swiss and not as readily available. Classic mornay sauce is traditionally made with Gruyère cheese (source). If you decide to try it, you can usually find it in the gourmet section of your grocery store.
- Dijon mustard (1 teaspoon). Adds flavor and blends very well with the ham and cheese.
- Salt & pepper to taste. You can add as much or as little as you like. Use freshly grated pepper for the best flavor.
Reduce heat to medium-low and simmer, whisking frequently, until thickened, about 5 minutes.
This recipe is really simple to make so there isn't much that can go wrong. However, my best tip is to keep that whisk moving when the sauce is on the stovetop. Burned croque madame sauce doesn't taste very good!
The sauce will solidify and become quite thick once it cools. This is fine. If you want a pourable sauce, you can heat it in the microwave to loosen it up. Heat on high for 30 seconds at a time, stirring in between, until it is the consistency that you would like.
❄️ Storage and Reheating
Be sure to refrigerate any leftover sauce in an airtight container within two hours of making it. It will keep in the fridge for up to 4 days.
You can also freeze it. It is best stored in a lidded mason jar. Make sure the sauce is completely cool, then fill the jar, leaving 1 inch at the top to allow for expansion. It will keep in the freezer for up to 6 months. (source).
To reheat, remove the lid and heat in the microwave or on the stovetop. Stir frequently while reheating to prevent curdling.
Yes it can. You can make it ahead and keep it in an airtight container in the refrigerator for up to 4 days. You can also make it ahead and freeze it. It will keep in your freezer for up to 6 months. See the Storage and Reheating section above for more information.
Most likely it is the cheese that is causing this grainy texture. There could be many causes, but here are some possible solutions (source):
* Be sure to remove the sauce from the heat before stirring in the cheese. If the cheese gets too hot, it can break down and become grainy.
* Do not use pre-shredded cheese. Buy the cheese in block form and shred it yourself. Pre-shredded cheese is treated with potato starch to keep it from sticking together. This can add a grainy texture and also adversely affects the cheese's meltability (Is that even a word?!) Regardless, it's better to shred the cheese yourself. A food processor can do the job nicely.
* Buy good quality cheese. Read the label. If it's loaded with additives and preservatives, leave it at the store!
This sauce is not gluten free because it uses flour. Check out "How to Make Gluten Free Roux for Keto Sauces + Soups" by Cotter Crunch to learn how to make a gluten free roux (the base of this sauce) that you can use in this recipe.
🔖 Related Recipes
These breakfast sandwiches have some pretty great sauces of their own. Check them out!
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Croque Madame Sauce
- 2 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 1 cup milk warmed
- ¾ cup shredded Swiss cheese
- 1 teaspoon Dijon mustard
- salt & pepper to taste
- In a small saucepan, melt butter over medium-low heat.
- Whisk in the flour until smooth. Let bubble without browning, whisking frequently for 1 minute.
- Gradually whisk in the warm milk, raise the heat to medium, and bring to a gentle boil, whisking frequently.Reduce heat to medium-low and simmer, whisking frequently, until thickened, about 5 minutes.
- Remove from heat and stir in cheese and mustard.
- Season to taste with salt and pepper.
- Transfer the sauce to a bowl and cover with a piece of plastic wrap pressed directly onto the surface of the sauce to prevent a skin from forming on the surface. Allow to cool.