Đâu Phu Rán Tâm Hành (Fried Tofu With Scallion-Oil Sauce)

Ingredients

• 4 scallions, coarsely chopped
• 1 2" piece ginger, peeled, coarsely chopped
• ¼ cup (packed) coarsely chopped cilantro
• 2 Tbsp. coarsely chopped mint
• ⅓ cup vegetable oil, plus more for frying (2–3 cups)
• 5 green Thai chiles, thinly sliced into rings, or 3 serrano chiles, finely chopped
• 1 Tbsp. fish sauce
• 1 Tbsp. unseasoned rice vinegar
• 2 tsp. instant dashi powder (preferably Hondashi)
• ¼ tsp. Diamond Crystal or Morton kosher salt, plus more
• Mochiko (sweet rice flour; for dusting)
• 1 14-oz. package firm tofu, drained, patted dry, cut into 12 pieces
• Bonito flakes (for serving)

Steps

1. Process 4 scallions, coarsely chopped, and one 2" piece ginger, peeled, coarsely chopped, in a food processor, scraping down sides halfway through, until finely chopped, about 15 seconds total. Add ¼ cup (packed) coarsely chopped cilantro and 2 Tbsp. coarsely chopped mint and pulse until finely chopped (be careful not to go so far that mixture becomes a paste), 10–12 pulses. Transfer herb mixture to a large heatproof measuring glass or small heatproof bowl.
2. Heat ⅓ cup vegetable oil in a large skillet over medium until just beginning to smoke, about 3 minutes. Carefully and slowly pour oil over scallion mixture (it will sizzle dramatically, so stand back slightly to avoid any spatter); reserve skillet. Stir in 5 green Thai chiles, thinly sliced into rings, or 3 serrano chiles, finely chopped, 1 Tbsp. fish sauce, 1 Tbsp. unseasoned rice vinegar, 2 tsp. instant dashi powder, and ¼ tsp. Diamond Crystal or Morton kosher salt; set scallion-oil sauce aside.
3. Place some mochiko in a small bowl. Working in batches, toss one 14-oz. package firm tofu, drained, patted dry, cut into 12 pieces, in mochiko until well coated on all sides, transferring to a wire rack set inside a rimmed baking sheet as you go.
4. Pour vegetable oil (2–3 cups) into reserved skillet to come ½" up sides. Heat over medium-high until hot but not smoking. Fry tofu in a single layer, turning occasionally, until very pale golden on all sides, about 6 minutes total. Transfer back to rack and lightly season with salt.
5. Arrange tofu on plates. Spoon scallion-oil sauce over and top with a small pile of bonito flakes.