In a 9 inch skillet with high sides, brown the sausage over medium high heat, chopping it up as it browns.
Once the sausage is cooked, reduce the heat to medium and mix in the flour until it is completely moistened.
Slowly add the milk, stirring constantly. Once all the milk as been added, continue stirring the gravy as it begins to simmer and thicken. Simmer the gravy for 3-5 minutes, until just before your desired gravy thickness is reached. (The gravy will continue to thicken as it cools, so stopping a bit early is a good idea.)*
Pour over your hot biscuits and enjoy!
Notes
*If you over thicken your gravy, no worries! Simply add a little more milk as you heat the gravy, stirring constantly, until it thins out to the place you would like it.