You can make any sauce that your mind dreams up by learning how to make roux correctly. The combination of fat and starch is the thickening agent for ANY liquid to make a sauce.
1) Render some duck fat or melt butter in a small sauce pan.
2) Add flour to the fat until it's wallpaper paste consistency.
3) cook the protein out of the flour. You'll see the roux go from brown to bubbly white.
4) add some type of flavorful broth in small increments until you reach the desired consistency.
You don't need a recipe for this, since it can all be done by eye. Once your roux is to the consistency you'd like, add some milk or chicken broth and watch it thicken. Add more stock, watch it thicken. When you add more liquid and it doesn't thicken any more, it's at the point that the roux cannot thicken any more liquid and you're done. Now, add condiments like mustard, garlic, mint sauce, and seasonings.
That's the recipe for every sauce known to man! (well, maybe not every).