One of my water sports friends told me about the roastbeef they have been having for Christmas Eve for many many years and as they are a family of many many people I figured that it must be as easy as it sounds. Turns out: it is.
Just take as much roastbeef as you think fit for the number of hungry mouths you want to feed. I usually think about 300 g per person, especially at Christmas when all scrooge-jokes are so out of place. This year, I ended up with 1500 g for a party of three, which seen from today's point of view - having to eat it mostly by myself for days without end - is a bit too much. But I felt festive and the roast looked so yummy.
Anyhow, on the day before you want to serve it, cover your roastbeef in dijon mustard, wrap it in aluminum foil and let it marinate over night in the fridge. No, no salt nor pepper whatsoever. See, how easy?
On the given day, take the roastbeef out of the fridge in time to allow for warming until room temperature. You don't want to thrust it into a really hot oven when it is still dreaming of winter wonderland.
Preheat the oven to 200°C and while you do so, let 250 g butter (you want about a thumb-thick soup of butter for the beef to swim in later on) melt in a roaster WITH LID. Don't think life can go on without a lid but aluminum foil as scraping burnt butter from your oven's walls is not the perfect way to spend Christmas Day. Trust me.
Place the roastbeef in the roaster and COVER IT WITH THAT LID. After 30 minutes, reduce the heat to 120°C and give it another 60 minutes in that cozy surrounding.
Serve with mashed potatoes and peas, as we did, or anything else which you like with that warm buttery-mustard taste.
Even without seasoning other than the mustard, it is amazingly tender and juicy and heavenly seasoned. Perfect for impressing mothers - if you are not snowed in - or any other circumstance in which you don't want to be stuck in the kitchen while your guests have all that great before-dinner drink all by themselves.
So: wash it all down with lots of red wine and sing some Christmas carols as dinner is taking care of itself.