Béchamel Sauce

Lumps form when flour clumps together before being fully incorporated into the liquid. The fix: strain the finished sauce through a fine-mesh sieve into a clean pot, pressing with a spoon. This removes every lump and takes 30 seconds. To prevent lumps next time, add milk in small portions of about 80 ml, whisking vigorously after each addition until completely smooth before adding more. The first two additions will form a thick paste — this is normal. Keep whisking and it will smooth out as you add more milk.

Mornay is simply béchamel with cheese melted in. Make your béchamel as described, then remove from heat and stir in 80 to 100 grams of grated Gruyère, Emmental, or a mix of both. Add 30 grams of Parmesan for extra depth. The residual heat melts the cheese — never put it back on direct heat after adding cheese or it can become stringy and grainy. A Mornay sauce is the base for macaroni and cheese, croque monsieur, and cauliflower gratin.

Béchamel keeps for 3 days in the fridge. To prevent a skin from forming on top, press plastic wrap directly onto the surface of the sauce while it is still warm — the wrap should touch the sauce with no air pocket. To reheat, warm gently over medium-low heat, whisking constantly. If it has thickened too much, add milk a tablespoon at a time while whisking until you reach the desired consistency. Béchamel also freezes well for up to 2 months.

The standard ratio is equal parts butter and flour by weight, with about 12 times their weight in milk. For this recipe: 40 grams butter, 40 grams flour, 500 ml milk. For a thicker béchamel (lasagna layers), increase butter and flour to 50 grams each with the same milk. For a thinner sauce (pouring consistency), reduce to 25 grams each. The 1:1 butter-to-flour ratio stays constant — only the milk amount changes the thickness.

A floury taste means the roux was not cooked long enough. After adding the flour to the melted butter, whisk constantly for a full 2 minutes over medium-low heat before adding any milk. The roux should bubble gently and look like a smooth, pale paste. You will notice the raw flour smell disappear and be replaced by a slightly nutty aroma — that is your signal. After adding all the milk, simmer the sauce for an additional 3 to 5 minutes. The starch granules need heat and time to fully swell and cook through.