First time doing a roast beef, help.

December 31, 2011 10:51 AM

MeFi cooks, please help me ace my New Year's Eve dinner of roast beef and mashed potatoes.

I'm making dinner tonight. There's 9 of us, my husband and me, plus several members of his family. We're at a an apartment at the beach, so I'm not cooking in my regular kitchen and I'm a little nervous. Also, on a whim I decided to make roast beef, which I've never made before. I'm a good cook, but roasted meats are not in my area of expertise.

I quickly Googled for a recipe so I knew what to get at the grocery store and came up with this, so I bought a 6.5 pound hunk of rump roast. It sort of looks like the one in this picture. Do I need to string it up? I got some string from the grocery store butcher. Also, I don't have a meat thermometer here, and I'll be cooking on an electric oven while I'm used to a gas one, so I'd like some advice on how much time this could take to get to a nice medium inside.

For flavor, I decided I'm going to make a ginger/garlic wet rub and let it sit for a while before putting it in the oven.

Please help make this a great first for me. I'll be checking back in case there's needs for follow-ups.

Also, I want to make mashed potatoes with a combination of regular and sweet potatoes, do they have different cooking times, or can I just boil them together?

posted by CrazyLemonade to food & drink (11 answers total)

You should really have a cooking thermometer. I can't imagine cooking a roast without one, especially for company (and I just checked your recipe, which requires one). Usually you can find one at the local grocery. This is extra vital if the oven does not have a working oven thermometer inside, and you have no idea if the oven temperature is accurate.

The roast is tied up to brown more area and keep more of it out of the liquid in the bottom of the pan (if that's what you're doing). If you're using the method in your link, definitely tie it up so less of it is sitting on the grill.

And yes, potatoes and sweet potatoes cook at different times. I think sweet potatoes get too waterlogged when boiled- I like to roast them, even for sweet potato pie or casserole. I think combining them with mashed potatoes is a little risky: you just end up with watered down flavored sweet potatoes that are faintly apricot colored. However, chunks of roasted potatoes and sweet potatoes can be very good together.
posted by oneirodynia at 11:04 AM on December 31, 2011 [1 favorite]

Seconding a cheap meat thermometer if you can get one quickly. It really helps to know when to pull the roast out, particularly if the meat cooks faster than you think in a strange oven. Otherwise I'd plan on 25-30 minutes a pound for medium (guessing from some internet searching and what's worked for me for rare/medium rare before). Try to give yourself enough time to let it sit and rest for 20 minutes or more after you pull it out. Sounds yummy....
posted by Cocodrillo at 11:20 AM on December 31, 2011

I will echo oneirodynia's advice both on cooking and tying up the roast and that you will want a meat thermometer - any big grocery store will have one, especially at this time of the year. Alternately, you can grab an instant read one somewhere.

I also agree with her about not combining potatoes and sweet potatoes in a mash. I would either roast them as she suggests, or I would mash each type separately and serve separate bowls of mashed potatoes and sweet potatoes (you can even do the mashed sweet potatoes ahead as they reheat well). We love to cut up regular potatoes, parboil them, toss them in a bit of olive oil and then roast them in the oven either around a beef roast in the roasting pan or in a separate pan, so you also could roast the regular potatoes with the beef roast and cook and mash the sweet potatoes separately.
posted by gudrun at 11:24 AM on December 31, 2011 [1 favorite]

Ok, seems like I definitely need a thermometer, I'll see if we can get to a Walmart later to buy one. The idea to serve the potatoes as roasted chunks also seems better than mashing them all together.

I changed the beef from the freezer to the fridge last night, but it seems as if it made no difference. I'm using the cold running water in the sink method right now...hopefully it'll defrost on time.
posted by CrazyLemonade at 12:08 PM on December 31, 2011

I find this a really helpful and not too fussy guide to cooking a roast and this one for cooking the veg.

I'd just serve roast veggies with the dinner. If you want them all to cook at the same time I'd parboil the normal spuds for say 5 minutes or so and they cook in about the same time as the sweet potato and just toss them all in together. If you toss them with some olive oil and put them around the roast all the yummy meat fat helps cook the spuds and they taste great.

A thermometer really helps getting the times right but beef can be very forgiving though it is better to under than over cook.

Oh this site is where I go to check my cooking times. the cranking up the heat at first and then dropping it method really helps.

Take out the meat to rest and if the veggies aren't nice and golden pop them back in and crank up the heat again but take out the pan juices for a nice gravy first.
posted by wwax at 12:12 PM on December 31, 2011 [2 favorites]

I have only used a themometer for my roasts in the past year or so because I was given one as a present by my very worried MIL. I cooked roast chicken, lamb and beef for years without one and just used time and the colour of the juices when poked with a skewer as a guide.
posted by wwax at 12:15 PM on December 31, 2011 [1 favorite]

I don't know that I'd combine regular and sweet potatoes in one dish - they're pretty different. The only way I can think of it coming out alright would be to dice them, toss them with olive oil & some salt or herbs, and roast them on parchment paper.

For mashed potatoes, I'm pretty partial to this Tom Douglas recipe:

Red Bliss Mashers/ Tom Douglas From Tom Douglas’ Seattle Kitchen (Morrow, 2001)
posted by lyra4 at 12:52 PM on December 31, 2011

If you do end up wanting to do regular mashed potatoes, I really recommend this Pioneer Woman recipe. It's uh, not exactly healthy (it calls for half-and-half and entire package of cream cheese) but my God were they good, and surprisingly easy.
posted by imalaowai at 1:26 PM on December 31, 2011 [1 favorite]

I've never used a thermometer and cooked many successful roasts. Beef is the most forgiving, just cook it at long and low (I'd probably do 1.5-2 hours at 140degC for ~3 kgs of meat like that). Poke it with a knife to check done-ness, don't get too hung up on the perfect level of rareness (just aim for some pink inside somewhere and you won't be disappointed). We recently tried the high heat then turn off the oven thing but ended up with very undercooked meat thanks to our weird oven, I'd only suggest trying that for an oven you're used to using and can be confident the heat is doing what you expect.

But the most important thing: let the meat rest before you cut it. At least ten minutes, fifteen or twenty is also fine. I didn't know how important this was until I had it spelled out to me and my roasts immediately became so much better. Letting it rest lets all the juices go back into the cells so when you cut it you get nice juicy meat. If you don't let it rest it doesn't matter how you cook it, once cut it will be tough and dry.

Don't mess around with mash, roast all the veggies. Potatoes will take about a 1 hour 20 to 1 hour 30 mins and the sweet potatoes will take only an hour (don't cook them longer, they go soggy). Pre-boiling the potatoes can bring them down to an hour too, but your meat is so big that you might not need to do that. Slightly over-roasted potatoes are crispy and great, so you've got some leeway there. Use olive oil and fresh rosemary if you have it. Also roast any carrots, beetroots, parsnips, squash, and whole onions you have hanging around, all for similar times to the sweet potatoes. Cut everything to about the same size pieces so they cook evenly, and check with a knife to see when they're done. All can be pulled out of the oven and reheated for serving, so don't worry if the timing isn't exact. Then serve with a salad or some lightly cooked green peas.

I'm an indifferent cook and yet can do a roast good enough to serve even guests I care about impressing. Don't over think it, it will all be good.
posted by shelleycat at 1:27 PM on December 31, 2011 [2 favorites]

Oh, I'd probably actually got for 155-160 degC when I think about it, our last oven ran twenty degrees cold so I got used to adjusting. Still, no need to make it too hot if you've got time to leave it in there.
posted by shelleycat at 1:28 PM on December 31, 2011

Thanks everyone for your answers. I got the thermometer and have all my potatoes and sweet potatoes ready to roast a bit later.

Happy new year, everyone!
posted by CrazyLemonade at 6:38 PM on December 31, 2011