Sweet Potato Fries (v) Recipe

Prep plums

If using fresh plums, pit and roughly chop to make about 1 cup. If using ume or salted plums, rinse to remove excess salt and finely chop.

Cook and reduce

In a small saucepan over medium heat, combine chopped plums, ketchup, rice vinegar, brown sugar, soy sauce, grated ginger, minced garlic, red pepper flakes, and 1/8 tsp salt. Bring to a gentle simmer, then reduce heat to low and cook, stirring occasionally, until the plums have softened and the mixture thickens slightly, about 10–12 minutes.

Blend and adjust

Remove from heat. Let cool slightly, then transfer to a blender or use an immersion blender and puree until smooth (or leave slightly chunky if preferred). Taste and adjust seasoning with remaining salt, a splash more vinegar for brightness, or a teaspoon more sugar if too sharp. Strain if you want an ultra-smooth ketchup (optional). Chill or keep warm at room temperature while frying fries.

Prepare sweet potatoes

Wash and dry the sweet potatoes. Using a mandoline or a very sharp knife, slice the sweet potatoes into chips about 1/8–3/16 inch thick for crisp tempura-style chips. Pat the slices very dry between paper towels to remove surface moisture—this helps the batter adhere and reduces oil splatter.

Make tempura batter

In a bowl, whisk together the all-purpose flour, cornstarch, baking powder, salt, and black pepper. Add ice-cold sparkling water and stir briefly with chopsticks or a fork until just combined; the batter should be lumpy and cold. Do not overmix. Keep the batter chilled in a bowl set over a larger bowl filled with ice if your kitchen is warm.

Heat oil

Pour vegetable oil into a heavy-bottomed pot or deep fryer to a depth of 2–3 inches. Heat oil to 350°F (175°C). If you don’t have a thermometer, test by dipping the side of a wooden chopstick or spoon — bubbles should form steadily around it.

Batter and fry

Working in small batches to avoid overcrowding, dip a few sweet potato slices into the chilled tempura batter, letting excess drip off, then carefully lower them into the hot oil. Fry until golden and crisp, about 2–3 minutes per batch depending on thickness. Turn once if needed with tongs or a skimmer. Remove fries to a paper-towel-lined tray to drain and immediately season lightly with a pinch of salt. Repeat with remaining slices.

Crisp finishing (optional)

For extra crispness, fry the drained chips a second time for 30–45 seconds at 375°F (190°C) then drain again.

Toss and keep warm

Place the finished chips in a large bowl, toss with 1 tablespoon neutral oil to keep them glossy and prevent sticking, and hold in a warm (not hot) oven at ~200°F (95°C) for up to 15 minutes while finishing remaining batches.

Place a generous pile of sweet potato tempura chips on a serving platter or individual plates. Spoon or drizzle the pickled plum ketchup over the top (or serve the ketchup on the side for dipping).

Sprinkle toasted sesame seeds and sliced scallions over the fries. If using, dust lightly with shichimi togarashi or smoked paprika for an extra layer of spice/smoke.

Serve immediately while hot and crisp, with extra pickled plum ketchup on the side.