In case you aren't sure where to find the weight listed on your packaging, here's a picture of mine. You want the net weight, not the tare weight, so you can see that my roast weighed 2.67 pounds (and I cooked this awhile ago, well within the "sell by" date, so don't worry, I didn't cook bad meat!!). Now then, when you want to season your meat, season all sides of it, even the ends!
The most challenging part of this recipe, is that it takes up the oven for about 2 1/2 hours. So, almost 3 hours before you're ready to serve (I add in an extra 30 minutes, for oven preheating time), preheat your oven to 500*. If your roast isn't already in the baking dish (I usually keep my roast in my baking dish, in the fridge after I season it), put it in whatever dish you want to roast it in, and put it directly into the preheated oven. No browning, no liquid added to your dish, and no cover to the dish.
Once your roast is in the oven, reduce your heat to 475* and roast it at 7 minutes per pound, then turn the oven off, and let it sit in the oven for 2 hours and 30 minutes. I cannot stress this enough: Do not open the oven during this time!! The heat that is in the oven will finish cooking your roast, very gently, allowing the outside to not burn, while leaving the middle a lovely medium rare pink.
Once the 2 1/2 hours are up, remove and slice your roast very thinly. This is not going to be hot, but it will be warm/room temperature, so you don't have to worry about it resting. It has been resting for the last 2 1/2 hours, after all!