So last night, I was thinking about what to eat with the 36 hour, 63C moose shoulder roast that had been in the water bath since Monday night after the deliciously successful trial run of the Sous Vide Supreme. This is where I disclose that I hate throwing anything away. If I roast meat, the bones go in the freezer for roasted-bone stock. If I roast beef ribs, the tallow goes into a plastic tub in the freezer for future potato roasting and oil poaching. If I make duck confit – and when I do, I tend to make it by the dozen – I save the duck fat because – it’s duck fat. It’s a great frying medium.
Anyway, it occurred to me that I should use some of the fat for frites to accompany the moose shoulder. I was thinking about a root vegetable and potato puree, but the moose was bound to be tender and I was looking for a textural contrast. I wanted to serve the moose with an herbed compound butter and shaved celery salad, and frites seemed simple enough to let those herby flavors shine.
This frying method comes from Robuchon and involves bringing the potatoes to cooking temperature from a cold oil start, and frying them only once. As a committed twice-fryer, I was skeptical of this cooking method until I tried it and was amazed. You should use it with medium-starch potatoes, like Yellow Finns, because russets or other high-starch potatoes can break (not always, but they’re more likely). It produces a perfectly crispy fry with a fluffy interior. It also eliminates a step, and yields a less greasy fry.
If you don’t have duck fat, or beef tallow, or another similar delicious fat, or you don’t enjoy the animal fats, use peanut oil. It lends a subtly nutty flavor to the frites.
4 large yellow (medium starch) potatoes, allumettes (3/8″)
6 cups grapeseed or canola oil (peanut is good also and yields an interesting taste)
2 cups duck fat or beef tallow
Place potatoes and both fats in heavy pan deep enough for oil to cover potatoes and leave at least 4″ at top. Bring to a full boil and cook, moving potatoes so they do not stick, from time to time, until deep golden and crisp. About 20-25 mins. Remove to towel-lined rack over a pan to drain. Season and serve immediately (or hold in 250F oven up to 20 mins for service).
Another note: with grilled or roasted beef, sometimes I find that compound butter makes the nicest sauce of all – it delivers a hit of creamy fat and bold flavor. As a bonus, you can keep what you don’t use in the refrigerator (or freezer, if you make more than you can use in a week), and slice off what you need at service. And if you have excess herbs – thyme, parsley, chives – this is a perfect use. Rosemary can be overwhelming and I don’t recommend using more than a little, if you use it at all.
1/2 lb (2 sticks) unsalted butter, room temperature
6 cloves garlic confit, stem ends removed, mashed to a paste
1 small bunch chives, minced
leaves from 6 sprigs thyme, minced
large pinch espelette pepper
salt to taste
Combine all the ingredients in a bowl with a fork until well incorporated; season to taste with salt.
Form into a log in waxed paper and then roll tightly. Refrigerate until service. Serve a slice with roasted or grilled meat.