Add medium-high heat then add the flour. Stir for a few minutes, while the flour cooks a little and smooths out, then add the garlic and cook a further 2 minutes.
⅓ Cup All Purpose Flour, ¼ teaspoon Garlic
Slowly start to add the heated milk, stirring constantly. A little at a time, stir stir stir, a little more, stir. This takes time, if you rush it you will end up with lumps in your gravy.
3 Cups Whole Milk
Once you have added all the milk you should have a nice smooth gravy. Season with salt and pepper.
1 teaspoon Salt, 1 teaspoon Black Pepper
Storage Instructions
Once cooled you can store in an airtight container in the refrigerator for up to 4 days. When you heat it back up again you may need to add more milk.
Notes
Depending on if you used bacon or butter to make your roux, will determine how much salt you need to add. I would definitely taste the white gravy before adding the salt so you know how much to add.