Classic Mornay Sauce

• servings: 2 cups
• total time: 15 minutes

Ingredients

4 Tbsp. butter

¼ cup all-purpose flour

2½ cups whole milk

½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt, plus more

1 pinch freshly ground black pepper or white pepper

1 pinch freshly grated nutmeg

4 ounces finely grated Swiss or Gruyère cheese

Directions

Melt 4 Tbsp. butter in a medium saucepan over medium heat.

Stir in ¼ cup all-purpose flour and cook, stirring constantly, until the paste cooks and bubbles but does not brown, about 2 minutes (don’t rush this step; you need to cook the raw flour taste out of the roux).

Slowly add 2½ cups whole milk while whisking to incorporate.

Bring mixture to a simmer, stirring constantly, then reduce burner to low heat and cook until sauce coats the back of a spoon.

Working in 2 or 3 additions, whisk in cheese, incorporating each addition just as the one before it is on the verge of fully melting; make sure to keep the heat low after the cheese goes in, as too much heat can cause the sauce to break.

Remove from heat and stir in ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt, a pinch of freshly ground black pepper or white pepper, a pinch of freshly ground nutmeg. Taste and add additional kosher salt as needed.

Notes

Mornay sauce is made from béchamel, one of the mother sauces in classic French cooking. You can use many different semi-firm cheeses for this, including cheddar, though Swiss or Gruyère is most traditional.