Mustard Cream Sauce

I have a very good meal for Christmas

We (two of us) enjoyed our tenderloin, which I prepared simply with the mushroom sauce that I also bought with you. I added more sliced fresh mushrooms to the meat and cooked them together for flavor. Then, the meat juices and cooked mushrooms I added to the sauce and that is what I served with potatoes and peas. Really good and I don't eat meat often because I am very picky in regards to flavor!