1. In a pan, put butter. Heat butter to melt.
2. Slowly add flour and fry till it loses its raw flavour.
3. Slowly pour in milk whisking all the time and mix well to remove the lumps.
4. Season it with salt, pepper and nutmeg. Whisk well to incorporate.
5. Continue heating on medium heat till it boils and the sauce thickens to desired consistency.
6. This sauce can be used to make various dishes like macaroni and cheese or Alfredo sauce, etc.