Béchamel's cheesiest child: gruyère and parmesan melted into the white mother. The sauce inside croque monsieur and over every gratin worth its crust.
What you need
Ingredients
Servings
4
500 ml
🥛 Milk ›
for the béchamel
50 g
🧈 Butter ›
50 g
🌾 Flour ›
80 g
🧀 Gruyère ›
grated
30 g
🧀 Parmesan ›
grated
1 pinch
🌰 Nutmeg ›
1 tsp
🟡 Dijon Mustard ›
Add all to shopping list
Mise en place
Before you start
5m
Prep
20m
Cook
25m
Total
—
Serves
Yield: About 550 ml
Equipment
Small saucepan
Whisk
Prep checklist
Milk — for the béchamel
Gruyère — grated
Parmesan — grated
2 steps
Method
1
Make a béchamel: blond roux from butter and flour, warm milk whisked in gradually, simmered 8 minutes to spoon-coating.
Learn the technique ›
2
OFF the heat, whisk in both cheeses and the mustard until glossy. Season with nutmeg, salt, and white pepper.
💡
Cheese added over the flame goes grainy and ropey. Residual heat melts it into silk — this rule is the whole sauce.
From the chef
Notes
Taste before serving and adjust salt and acid — the last 30 seconds of seasoning matter more than any single ingredient.
Afterwards
Keep, reheat & pair
Storage
Airtight jar in the fridge, 3–5 days. Press plastic wrap onto the surface of starch-thickened sauces to stop a skin forming.
Freezing
Most sauces freeze 2–3 months; freeze in ice-cube trays for single portions. Emulsified butter/egg sauces don't freeze — they break on thawing.
Reheating
Reheat gently over low heat, whisking; butter- and egg-based sauces split when boiled. Loosen with a spoonful of warm water or stock.
Make ahead
Most sauces keep 3–5 days refrigerated and freeze in ice-cube trays for instant single portions. Emulsified butter sauces are best made within the hour.
Wine pairing
Follows the dish it dresses.
Beer pairing
Follows the dish it dresses.
On the plate
Serve it with
Sides
·
Croque monsieur
·
Cauliflower or leek gratin
·
The world's most legitimate mac & cheese
Garnish
A final swirl of butter or oil
Fresh herbs
Taste map
Flavor profile
Sweet
Salty
Sour
Bitter
Umami
Heat
Per serving
Nutrition
240
kcal
10g
protein
10g
carbs
17g
fat
3g
fiber
520mg
sodium
When it goes sideways
Troubleshooting
Lumps. The liquid went in too fast or too cold. Whisk hard; if lumps persist, pass the finished sauce through a fine sieve — no one will ever know.
Tastes like flour. The roux needed another minute of cooking before the liquid. Simmer the finished sauce 5 extra minutes and the raw edge cooks out.
A skin formed. Press plastic wrap or buttered parchment directly onto the surface while it holds.