Slice the breakfast sausage and place in a warm pan. Cook the sausage according to the instructions. Remove them to a paper towel to drain. Place your biscuits into the oven to cook according to the instructions on the can. Pour grease out of the pan you used for the sausage, adding back in only what you want to use to make the gravy. For one to two people, use about 2-3 T of grease. Over low to medium-low heat, add equal amount of flour to the grease and whisk immediately. After 2-3 minutes, whisking constantly, pour in about a cup of milk. Use more for thinner gravy. Add salt and pepper to taste. Let the gravy warm up over low heat, stirring occasionally. Cut prepared biscuits in half pour gravy atop them.