Sweet Potato Tempura Roll Recipe

Prep and par-cook

Peel the sweet potatoes and cut into uniform batons about 1/4" x 3". Place in a pot of cold water, bring to a gentle simmer, and cook for 3–4 minutes until just tender but still firm. Drain and pat dry completely with a kitchen towel. Sprinkle with 1 tsp kosher salt and set aside to cool.

Heat oil

Pour vegetable oil into a deep pot or heavy-bottomed pan to a depth of about 3 inches (use enough to fully submerge the pieces). Heat to 350°F (175°C). If you don't have a thermometer, a small piece of batter should sizzle and float immediately.

Fry sweet potato

Working in small batches, dunk the par-cooked sweet potato batons in the prepared tempura batter (coat lightly) and fry until the batter is crisp and pale golden, 2–3 minutes. Do not crowd the pan. Remove with a slotted spoon and drain on a paper towel-lined tray. Keep warm in a single layer so they remain crisp.

Make the batter just before frying. In a bowl, combine 3 tbs all-purpose flour, 2 tbs cornstarch, and 1 tsp baking powder. In a separate small bowl beat 1 large egg. Add the egg to 3 cups ice cold sparkling water (or ice water) and stir briefly. Add the egg-water mixture to the dry ingredients and fold very gently with chopsticks or a fork—do not overmix. A few lumps are okay. Keep the batter bowl in a larger bowl with ice or add a couple of ice cubes to the batter to keep it chilled while frying. Use immediately; discard any leftover batter after frying to avoid sogginess.

Rinse 2 cups short-grain rice under running water until the water runs clear. Drain and combine with 2.2 cups water in a rice cooker or pot. Cook according to rice cooker instructions or bring to a boil, reduce to low, cover and simmer 15 minutes, then rest covered for 10 minutes off the heat.

While rice cooks, warm 3 tbs rice vinegar, 2 tbs sugar and 1 tsp kosher salt in a small saucepan over low heat just until sugar and salt dissolve. Do not boil. Transfer the cooked rice to a large wooden or plastic bowl (avoid metal). Gently fold the vinegar mixture into the rice with a wooden paddle or spatula using a cutting-and-fanning motion to cool and season: slice through the rice rather than stirring vigorously so grains stay distinct. Fan or let cool to room temperature before rolling.

Prepare workspace with a bamboo sushi mat wrapped in plastic wrap (this prevents sticking). Lightly brush the mat with 1 tsp vegetable oil if desired. Place a sheet of nori shiny side down on the mat.

With damp hands, take about 3/4 cup of the prepared sushi rice and evenly spread it over the nori leaving a 1" strip at the far top edge free of rice. Sprinkle toasted sesame seeds over the rice if using.

Flip the nori so the rice side is down on the mat (optional for inside-out roll). If you prefer inside-out (rice on the outside), place a sheet of plastic over the rice, flip the nori and peel away the backing so rice faces out.

Place 3–4 pieces of the warm tempura sweet potato along the near edge of the nori (closest to you), leaving a small gap at the edges. Add a thin line of spicy mayo if desired: mix 2 tbs mayonnaise with 1 tbs sriracha and pipe or dollop along the sweet potato.

Use the bamboo mat to roll the nori over the filling, tucking firmly but gently to create a tight cylinder. Continue rolling until sealed. If making inside-out rolls, roll with the seam down and press gently to set the rice.

Using a very sharp knife moistened with water and wiped between cuts, slice each roll into 6–8 pieces. Clean and re-moisten the knife between slices to get clean cuts without tearing the rice.

Arrange on a platter and serve with soy sauce, pickled ginger and wasabi. Serve immediately so the tempura remains crisp.