I guess the name kinda says it all? I’ve been using this sauce as a base for years. I always add cheese. I think it’s bland otherwise (which is probably why it’s usually a MOTHER sauce and not the finished BABY sauce).
Melt some butter into a pan, and stir in flour to form a paste. I can’t give you exact measurements because 1. This is cooking and measurements are completely unnecessary and 2) It will depend on how much you’re making and how many you’re cooking for. A good general rule is equal parts of each.
Then, slowly whisk in cream. Surprisingly a little bit goes a long way. You can cut in milk also. After I brought the sauce to a simmer I added garlic, white cheddar cheese and spinach. The sauce will simmer for as long as you need it too, but it will continually thicken, so you might need to add more milk or cream if you’re waiting for the rest of your dinner.