Step 1: In a 10 inch pan and on medium high heat - preferably cast iron brown the ground sausage
Step 2: keep any fat that cooks off - if you think it's too much like covering the meat then drain half.
Step 3: Push meat to one half of the pan and reduce temp to low
Step 4: If you do not have a lot of fat due to a leaner sausage melt the butter
Step 5: Once melted and meat moved sprinkle the flour over the fat/butter
Step 6: Whisk together with the fat/butter until color changes to a light golden brown.
Step 7: Incorporate the meat back into the roux from the flour and fat/butter
Step 8: Turn back to medium high heat and slowly add 1 cup of milk at this point a whisk may be cumbersome but will help get the flour mixed in well
Step 9: Once the milk is incorporated keep stirring to get any lumps out. Once it bubbles a little the gravy will thicken at this point add a little of the other cup of milk until consistency of liking is reach.
Step 10: After desired sauce consistency acheived turn off the heat and stir in pepper and sat to taste.
Step 11: Enjoy over biscuits, rice, toast or even by itself (why not!).