Start by heating the milk over low heat until just before boiling.  Keep an eye on the milk as you don’t want it to boil, that’s why I heat it over low heat. If the milk looks like its at that boiling point and your butter hasn’t completely melted yet, then just turn off the heat under the milk until you are ready to use it.

In another pan start melting the butter over medium to medium-low heat while the milk is warming. Cutting the butter into about teaspoon slices right into the pan will melt the butter quicker.

When butter is melted, add the flour about a Tablespoon at a time, whisking constantly to prevent lumps. Stir until smooth, about a minute. 

Now slowly add the hot milk to the melted butter and flour mixture. I slowly pour about a half cup of milk at a time, whisking constantly. After incorporating the first cup of milk, you should be able to slowly pour the other two cups in all together.  Stir often.

You want to continue cooking the bechamel sauce until it turns a nice, light golden color. This should only take about 5-6 minutes. If after 5-6 minutes the golden color hasn’t started to show yet, then turn up the heat slightly and continue to cook another minute or two.

Remove the bechamel sauce from the heat and add in the kosher salt and some grated nutmeg. 

The sauce will thicken a bit as it cools.