Step 1

Cut the tofu block crosswise into 6 equal segments, then cut the segments into 3 equal pieces to make 18 pieces. Press the tofu pieces between paper towels to dry them. Set aside.

Step 2

Add the scallions, fish sauce and sugar to a medium heatproof bowl and place the bowl next to the stove. Place a wire rack in a baking pan or sheet and place next to the stove as well.

Step 3

Add 2 1/2 inches of oil to a medium heavy-bottomed saucepan or high-walled cast-iron skillet set over medium-high heat. When the oil reaches 190 degrees F (see Cook's Note), ladle out 1/2 cup of oil and slowly pour over the scallion mixture; it should sizzle. Set aside the scallion oil while you fry the tofu.

Step 4

Heat the remaining oil in the saucepan to 375 degrees F. Add the tofu and fry until golden, 8 to 10 minutes. Transfer the tofu to the wire rack-lined baking pan to drain.

Step 5

Divide the tofu among 2 to 3 bowls of rice. Stir the scallion oil to incorporate the oil with the scallions, then ladle generous spoonfuls over the tofu.