Get the flour, butter, and milk ready for the sauce thickness you want and keep them close to the stove. The cooking process will be fast, so have everything nearby.

Heat the saucepan on medium heat.

Put the butter in the pan and melt it without browning or burning. Then add the flour as soon as the butter is melted. You can add both at the same time, just make sure the butter doesn’t brown on the edges before melting in the center.

Use a whisk to mix the butter and flour until they are well-combined. Cook the mixture for 3-5 minutes, adjusting the temperature to prevent browning. It should start to smell slightly sweet and nutty. It’s okay if it clumps together at this stage, just keep stirring.

With one hand holding the whisk, pour in the milk a bit at a time (as little as a quarter cup at a time) and whisk it quickly, being careful not to splash. It might be helpful to have someone assist you at this stage. The bechamel should take on a stringy consistency.

Keep adding milk while whisking, scraping along the edges of the saucepan to mix in any bits sticking to the edges.

Once all the milk is in, keep cooking for 3-5 minutes while stirring continuously.

Turn off the heat and season as you like (optional: ½ teaspoon salt and ¼ teaspoon nutmeg.