Cook sausage in a skillet until browned and crumbly. Remove to paper towels to drain. Add butter to skillet and melt. Add flour and stir into butter to form a roux, adding olive oil if necessary to incorporate all the flour. Add milk and cook, stirring until gravy is thickened and smooth.
Bake at 350 for 30-40 minutes or until biscuits are cooked through and golden
If gravy is lumpy, use an immersion blender to smooth it out