Broiled Flank Steak with Mustard Mashed Potatoes
Prep time: 15 minutes for the steak, about 45 minutes for the mashed potatoes.
Serving size: flank steaks are sold in 1-2 pound pieces; buy according to how many you are feeding. A pound feeds 3-4.
For the mashed potatoes: 4 large russet potatoes (about 2 pounds) feeds 3-4 or, in my house, 2 with leftovers.
For the flank steak:
1 flank steak; my piece was just under one pound
2 tablespoons soy sauce
1/2 cup decent red wine
1 teaspoon black pepper or three grinds of the peppermill
1-3 large garlic cloves, crushed and peeled
1 tablespoon olive oil, optional
For the mustard mashed potatoes:
3-4 large russet potatoes, peeled and chunked
1 egg, optional
unsalted butter, ideally Kerrygold or another European full-fat butter.
Dairy of your choice: buttermilk, milk, half-and-half, or heavy cream
2 tablespoons of your favorite mustard: I use Amora or Dijon
Salt and pepper
Marinate the flank steak:
1-24 hours before cooking, place the flank steak in a broiler-proof baking pan. Pour the soy sauce, red wine, garlic, pepper, and olive oil, if using, over. Cover with foil and refrigerate if marinating ahead of time.
Bring meat to room temperature before broiling.
Set your oven’s shelf in the second slot from the top, which allows the meat to cook without burning. Preheat your broiler.
Slide the flank steak into the oven. Cook five minutes, then turn the steak over and cook an additional five minutes. If you like meat more well done, turn it over again and cook an additional five minutes for a total 15 minutes cooking time. The meat will continue cooking off the heat.
Remove the flank steak from the oven. Tent loosely with foil. Allow to rest for about ten minutes. Slice thinly.
That’s it.
For the potatoes:
Bring a large pot of salted water to a rolling boil. Add the potatoes. Cook until tender, about 20 minutes.
Drain and dump them into a large bowl.
Mash the potatoes with a masher, or, if you are on a quest for mashed potato perfection, a mixer or food mill. If you’re using the egg, now is the time to stir it in, fast. Add the butter and dairy in amounts you see fit. When the mash tastes right to you, stir in the mustard, beginning with two tablespoons. Taste: this may be enough. If not, add a bit more. Do not salt until you have the mustard balance right, as mustard is salty. Once you’re satisfied with the mustard, taste for salt and pepper.
The flank steak keeps, refrigerated, up to three days, though we never have it around that long. Although mashed potatoes keep in the fridge, they become stodgy; eat them quickly. Or form leftovers into potatoes cakes and fry them in butter, olive oil, or duck fat.
Notes: Do not salt the flank steak. Soy sauce is salty enough. Dark soy, or “mushroom-flavored soy sauce,” is nice here. Sometimes I use olive oil, sometimes I don’t. It’s great either way. We love garlic, so use lots. Use as much or little as you wish. Lining your baking dish with foil or baking paper saves washing up.
Amounts of butter and dairy for the potatoes are not given, as mashed potatoes are a deeply personal food: please add to your taste. If you are using a raw egg, please use a fresh one from a friendly farm where chickens live happy chicken lives. Do not feed raw eggs to the ill, elderly, very young, or immunosuppressed and then sue me when they fall ill. Use common sense–and the best possible eggs. If in doubt, don’t use the egg. Thank you.