In a saucepan, melt the butter over medium heat.
Once the butter is melted, add the flour to the pan.
Stir the flour continuously with a whisk until it forms a smooth paste (roux) and starts to bubble slightly, about 2-3 minutes. Be careful not to let it brown.
Gradually pour in the milk while whisking constantly to prevent lumps from forming.
Bring the mixture to a gentle simmer, stirring frequently. Allow it to cook until it thickens to a creamy consistency, about 8-10 minutes.
Add a pinch of ground nutmeg, salt, and white pepper to taste. Continue stirring until well combined.
Once the sauce reaches the desired consistency, remove it from heat. Use immediately in your favorite dishes like Lasagna, Cannelloni, or Pasta, or let it cool down before storing in the refrigerator.
