Heat a large saute pan over medium heat and add in the sausage. Cook for about 6-8 minutes, stirring and breaking it up occasionally, until cooked through. Remove the cooked sausage with a slotted spoon onto a plate or into a bowl and set aside.
Put the pan back over the heat and sprinkle the spice rub and flour into the reserved sausage drippings. Whisk thoroughly so no white flour or lumps remain and cook for 1-2 minutes.
Slowly pour in half of the milk, whisking vigorously to get rid of any lumps. As the sauce starts to cook it will thicken up. Whisk in the rest of the milk, add the cooked sausage back to the pan and let the gravy simmer for 2-3 minutes, or until it has thickened enough to coat the back of a spoon. (Basically, it should look like gravy.)
Split the warm biscuits in half and place one on each plate. Top the biscuits with the warm gravy and serve immediately.