I got this out of the old Merle Ellis the Butcher newspaper column. Don't know whatever happened to that guy. This is a real simple but really good recipe.
1 1lb package sausage (I like Jimmy Dean Sage flavored, I like sage. Don't use hot)
1 medium onion, sliced thin (actually, even though I love onions, I think a half-onion is plenty)
3 tablespoons flour
3 cups milk, heated
Salt and Pepper
Heat a large skillet over medium high heat. Put the sausage in the skillet (don't add oil, just drop it in) and brown thoroughly, breaking up the sausage into fine pieces with a spatula as much as possible. Stir in the onion and continue to fry until onion is softened, stirring occasionally. Sprinkle flour, salt, and pepper over sausage-onion mix and stir, continue to fry for a few minutes. By now the skillet should have a fairly heavy crust on the bottom. Pour in the milk all at once and stir constantly, scraping the bottom of the skillet. The milk will dissolve the crust and the gravy will turn a light gold, thicken, and get bubbly. Cook for a couple more minutes. Makes a little over a quart of gravy.
One of my favorite meals is pork chops cooked any way you want with potatoes and this gravy.