Classic Béchamel Roux Sauce for Lasagne

1. Warm the milk in a small saucepan or jug over low heat until it's just steaming — not boiling. Set aside. Warming the milk prevents lumps forming when you add it to the roux.

2. Melt the butter in a medium, heavy-bottomed saucepan over medium-low heat. Once it's foaming and fully melted but not browning, add all the flour at once.

3. Stir immediately and continuously with a wooden spoon or balloon whisk. Cook the roux for 2 minutes, stirring the whole time, until it smells slightly nutty and has turned a pale golden colour. This cooks out the raw flour taste.

4. Remove the pan from the heat. Add the warm milk a little at a time — start with just a splash — whisking vigorously after each addition to fully incorporate it before adding more. This gradual technique is key to a lump-free sauce.

5. Once you've added roughly half the milk and the sauce is smooth, you can add the rest more freely, still stirring. Return the pan to medium heat.

6. Cook the sauce, stirring continuously, for 5–8 minutes until it thickens to a consistency that coats the back of a spoon. It should be thick enough to layer in lasagne but still pourable.

7. Season generously with salt, pepper, and the nutmeg. Taste and adjust — the nutmeg should be subtle but present. Your béchamel is ready to use.