In a medium sauce pan heat milk over medium heat until it just reaches a light simmer then turn off the heat and set aside.
2 ¼ cups whole milk
In a small saucepan, melt butter over medium heat.
4 tablespoon unsalted butter
Add flour and whisk into the butter and cook for 3 minutes, stirring often.
4 tablespoon all purpose flour
Now add the warm milk one ladle full at a time while mixing it into the flour and butter mixture.
Keep adding one ladle at a time and mixing until all of the milk is used.
Now add Parmesan, nutmeg, salt and pepper.
¼ cup grated Parmesan, ⅛ teaspoon grated nutmeg, ⅛ teaspoon kosher salt, a few swirls of freshly ground black pepper
Remove from the heat and add a piece of plastic wrap over the besciamella making sure to lightly press the plastic wrap on to the surface of the sauce to prevent a film from forming.