An easy, do-ahead, spectacular, and delicious way to serve beef. It's a less full-on version of "Boeuf en Croute" and is a big hit with family and my guests. Use flavourful mushrooms if you can - like criminis, portobellos or even porcinis or morels. For the wine, choose something rich you would actually drink, like a good Shiraz. Great served with asparagus.