Almost as much as hearty soups and homemade bread, dropping temperatures put me in the mood to toss a giant hunk of meat in the oven. There are lots of delicious things to roast.
You could roast a leg of lamb (mmmm...lamb).
You could roast a chicken (though I'm lousy at that).
You could roast a duck (I've done it, but it's definitely not an everyday occurrence).
You could roast a whole fish (haven't done that - I find it easier to broil fish, but then again I've never bought a whole one).
But I want to talk about roasting that's EASY. In my experience, there are two things that are really easy to roast.
The first is pork loin. Specifically, a half boneless pork loin. All of those attributes are important: if you want an easy task, you want a boneless cut. You want a loin, not a tenderloin; tenderloin is delicious (and I love it for the grill), but it's much smaller, and more expensive. And you want half the loin: the whole thing is nearly three feet long and a pain in the neck to work with - even if you're feeding a huge crowd, you might find it easier to work with two half loins than a whole one. (Obviously, if you want to feed lots of people and use two half loins, you could cut a whole one in half. But if you want to buy it ahead of time, you better have a ton of space in your freezer!)
I stumbled upon this easy-roasting project when I found half pork loins on great sales during my student days. In the intervening years I've learned a few things about making it easy.
First of all, you want a piece of even diameter so it cooks evenly. Secondly, you want almost no fat on it EXCEPT that you want a nice even fat cap, about 1/8" thick, completely covering one side. When you roast it, that will be the top; and as it roasts, the fat will slowly melt and baste the meat, so although it's a fairly lean cut, it will be very moist.
Now, about how to roast it. You want to roast meat with a marinade, of which there are three essential components. The first is FAT. A coating of fat will seal in the meat's moisture as the outside cooks. This could be olive oil, melted butter, duck fat - whatever. The second is ACID. The acid will help to start breaking down the meat a bit. You could use vinegar, lemon juice (or another citrus), or even a very tart yogurt. Finally, you want any seasonings you'd like to start infusing into your meat. (At this stage, salt is optional - I would say it's better to wait to add salt until the very end.) So, at the simplest level, the marinade could include just oil and vinegar - that would be effective, but it wouldn't add any extra flavor. And remember, I go for more is more. Of course, that doesn't have to mean more work. If you think about it, salad dressing has all the ingredients (fat, acid, and seasonings). I consider golden Caesar dressing a go-to marinade for all applications - it somehow pairs perfectly with beef, pork, chicken, fish, AND vegetables. I always have a bottle on hand. If you have a few extra minutes, you can make a marinade from scratch. My go-to marinade consists of balsamic vinegar, olive oil, minced garlic, and freshly-ground black pepper and rosemary. (If you don't have a mortar and pestle, you can chop up the pepper and rosemary with a chef knife.)
I also have a variation on marinade for pork loin specifically: just a rub of oil and herbes de Provence, or even dried oregano and oil. Simple, but delicious.
The traditional method of roasting meat is to start by browning all sides in a skillet in some fat. This searing locks the juices in and prevents the whole piece of meat from drying out during the roasting time, because once the outside is cooked, it won't bleed its juices any more (unless it is cut). But as is foreshadowed in my insistence on a fat-containing marinade, I take a different approach to that. I no longer remember where I read this tip, but I follow it religiously: whatever the rest of the roasting instructions, I start every roast with 15 minutes in an oven preheated to 500F. Then I drop the temperature to the regular roasting temperature (generally 325 or 350 degrees), and give it the rest of its time. About 22 minutes a pound is standard for pork loin (though those first 15 minutes are really equivalent to 22 minutes in view of the higher temperature).
Probably you should use the USDA guidelines on internal temperature to make sure the pork is done, but I'll be honest: I go exclusively by color (which requires either guessing that the meat is done until after it's rested, or cutting it to check doneness BEFORE it's rested, which is a no-no: a roast should sit ten minutes at least after coming out of the oven so that the juices can re-absorb and don't all just run out when it's cut. But I do it anyway, and then smoosh the meat back together to re-close the gash). For a pork loin roast, I want the center to be MOSTLY greige, but in the very middle, I want to see a blush color. Once the whole roast is greige, it's too dry.
So one day I got to thinking: it's too bad that there's not a cut of beef with the virtues of the pork loin. Something without a ton of tough connective tissue that requires long cooking. And without a lot of fat ribbons that need trimming - with the whole diameter of the roast just plain meat. With a nice fat cap for self-basting. Not with a lot of fine marbling to keep it tender, since that's really expensive beef - just a plain, not-super-tough cut with a moderate diameter, so it roasts fairly quickly and doesn't get tough.
Then one day in the grocery store I noticed eye of round roast on sale and realized that I am an idiot. It's beef straight through (no fat to trim out of the middle). It's not too big around. It's not all marbled like a pricey rib eye - but it's a light red color, not too tough (compared to, say, the dark red of a chuck roast, which has to be cooked for hours to be tender). And while eye of round roasts are cut less uniformly than than pork loin roasts, you can find one of fairly even diameter and with a nice even fat cap. One caveat: if you like your beef well done, this cut may be too tough by the time it's finished. I eat my beef medium-rare, and this roast cones out perfectly. (Not as tender as a rib eye, say, but plenty tender to be delicious!)
I'm not sure this comes through, given the length of my musings on this topic, but you could make either of these with less time actually working than it takes to read this post. A few minutes to slather the roast with marinade and pop it in a roasting pan (while the oven preheats); a few seconds to change the temperature from 500F and then reset the timer. It's ridiculously easy.
And if you want the rest of the meal to be equally easy, you can skip the roasting rack by setting your roast on a pile of winter vegetables (in fact, any vegetable that can handle a long cooking time). I recommend small cubes of potato (3/4"); large cubes of onion (1.5"), NOT slices (onions burn a LOT faster than potatoes); halved Brussels sprouts; and cubes of squash, turnips, or carrots (or all of those). Add a drizzle of oil and salt and pepper. I buy bags of frozen butternut squash, turnips, and Brussels sprouts, so this is barely more complicated than pouring bags into the bottom of a large roasting pan. I'd ballpark it at a pound of veggies per pound of meat, but if you like lots of veggies you could make a separate potato dish (or another starch - or no starch) and just fill the bottom of the roasting pan with the other veggies.
Oh by the way - I know marinade is technically something you soak meat in over time, not something you just slather on meat right before it goes on the heat (the sense in which I've been using the word). But I think you get what I'm saying, yes?