Smoky fish butter elevates the simple baked potato

Baked potatoes and mashed potatoes are deceptively named because they’re as much about the potatoes as what you put into them, if not more. Russet potatoes, the go-to for baked potatoes, are dry and bland out of the oven, their interior not (yet!) creamy and cloudlike. They’re thirsty – for butter.

But first, to bake them so that their skins crisp and the insides dehydrate even more, wash and dry the skin well and poke the potato all over with a fork. (While russet potatoes are considered low-moisture for a potato, they’re still 80 percent water.) So that the skin is flavorful and not at all tough, rub it lightly with oil and salt. Then bake the potato directly on an oven rack, or on a cooking rack set over a baking sheet. This allows heat to circulate for even cooking and moisture to escape, unlike when potatoes are wrapped in foil.

This baking method will result in chip-like skin and dry and bland flesh. Lots of butter and salt will fix that, but butter can do so much more.

Here, it’s filled with scallions, dill and hot-smoked fish for a combination that strikes a similar balance of rich, smoky, onion-y and fresh as traditional baked potato toppings of cheddar cheese, bacon and chives. The fish butter will last for up to a week in the fridge, ready to be slathered on hot potatoes as well as toast, hot rice or pasta, steamed vegetables, jammy eggs, and so on. It’s amenable to additions you like with smoked fish, like horseradish, capers, lemon zest, everything bagel seasoning and even sour cream. But keep the fish.

Hot-smoked fish is like the bacon of the sea. It’s rich, smoky, salty and meaty. It’s made by smoking trout, salmon, mackerel, white fish or tuna at a high temperature so that, unlike the glistening smoked salmon on your bagels, the fish is fully cooked, firm and easily flaked with fingers. Look for it vacuum-packed (and sometimes labeled smoked-roasted) near the cold-smoked salmon. It’s great to have around to add to salads, sandwiches, pastas, creamy dips and grain bowls.

Once your potatoes are cracked into, you can finally hydrate them with a not insignificant amount of the fish butter. The potato’s flesh will shift from matte and beige to fluffy and speckled golden. It’s a humble yet gratifying kitchen transformation. A delicious one, too.

Baked Potatoes With Smoked Fish Butter

A baked potato slathered with butter is great, but add hot-smoked fish, scallions and dill to that butter, and you get a potato that’s smoky, onion-y and fresh. The recipe makes about 1 1/2 cups of fish butter, which can be stored in the refrigerator

for up to seven days.

4 large russet potatoes (2 pounds total), scrubbed

1 tablespoon extra-virgin olive oil

Fine salt

1 stick (8 tablespoons) unsalted butter, softened

1 cup flaked, skin-off hot-smoked trout or salmon (from about 5 ounces fillets)

1/4 cup finely chopped fresh dill, plus more for serving

3 scallions, thinly sliced, plus more for serving

Freshly ground black pepper

Position a rack in the middle of the oven and another one directly below, and preheat to 400 degrees.

Poke holes all over the potatoes with a fork. In a medium bowl, toss the potatoes with the oil and a pinch of salt. Place the potatoes directly on the oven rack, and set a large, rimmed baking sheet on the rack below to catch any drips; reserve the bowl. Roast for 1 hour or until the potatoes offer no resistance when a sharp paring knife is inserted into their centers.

Meanwhile, transfer the butter to the reserved bowl and use a spoon or fork to mash it. Add the fish, dill and scallions, and mash and stir to combine. Season to taste with pepper; the fish is quite salty, so you probably won’t need additional salt. You should have about 1 1/2 cups of fish butter.

When the potato is tender but still hot, carefully make an incision lengthwise, then push the ends in to crack it open. Using a fork, fluff the steamy interior, then add 1 to 2 tablespoons of the fish butter and mix to combine. Garnish with an additional bit of the butter, the dill and scallions and serve right away.

Yield: 4 servings