Ingredients:

  • 3 tbsp unsalted butter
  • 3 tbsp all-purpose flour
  • 2 cups whole milk, room temperature
  • 1/4 tsp ground nutmeg
  • 1/2 tsp fine sea salt
  • 1/4 tsp white pepper
  • 1 cup Gruyère cheese, freshly grated
  • 1/4 cup Parmesan cheese, freshly grated

Instructions:

  1. Melt the butter in a heavy-bottomed saucepan over medium heat until it foams.
  2. Stir in the flour and whisk constantly for 1-2 minutes until the roux reaches a blonde color and smells slightly nutty.
  3. Slowly pour in the milk a splash at a time, whisking vigorously after each addition to prevent lumps.
  4. Bring the mixture to a gentle simmer, stirring constantly until the sauce thickens enough to coat the back of a spoon.
  5. Stir in the salt, pepper, and ground nutmeg.
  6. Remove the pan from the heat to ensure the cheese does not separate.
  7. Add the grated Gruyère and Parmesan in handfuls, stirring gently until the sauce is glossy and the cheese is fully melted.