Place sauce pan on the stove, add butter and melt.
Add half of the flour and whisk. into butter. Keep over slow to medium heat.
Add the remaining flour and whisk in over a medium heat setting. Whisk and reduce until it bubbles and it has slightly turned light brown. The roux needs to be smooth.
Reduce heat and pour in slowly milk and whisk in.
Increase heat to medium and keep on whisking to incorporate sauce ingredients. Keep on whisking, the sauce will get formed and will thicken.
When you are happy with the consistency, season with salt, pepper, and grated nutmeg. Adjust flavor to your liking.
At this point, you can choose to add cheese too to make a cheesy sauce mornay. Use the sauce in another dish or serve with meats or veggies.
Video
Notes
Use butter or lard. You can use olive oil or sunflower oil too but the taste won't be that great compared ot butter or lard.
For your seasoning taste test and adjust.
4 servings is an estimate and depends on the way you use this sauce.