Set a large nonstick skillet or wok over medium-high heat. Set a plate and a small bowl by the stove so they are ready when you need them.

Prep the tofu: Put the torn tofu in a medium bowl. Sprinkle 2 teaspoons of the cornstarch over the tofu and toss gently so the pieces are lightly coated.

Mix the sauce: In the small bowl, stir together the soy sauce, sugar, crushed red pepper flakes, the remaining 1 teaspoon cornstarch, and 1/3 cup water until smooth. Set this sauce aside.

Cut the eggplant, bell pepper, scallions, garlic, basil, and lime if you have not already done it. Keep the scallion whites and greens separate so they go in at different times.

Brown the tofu: Add 2 tablespoons of the oil to the hot skillet. Tilt the skillet so the oil coats the bottom.

Add the tofu to the skillet in a single layer. Cook it without moving it for 3 to 4 minutes, until the bottom sides look golden brown.

Turn the tofu pieces with tongs or a thin spatula. Cook for 3 to 4 minutes more, turning once or twice, until several sides are browned and the pieces look firm. Transfer the tofu to the plate.

Cook the vegetables: Add the remaining 1 tablespoon oil to the same skillet. Add the eggplant and spread it out as evenly as you can.

Cook the eggplant for 4 to 5 minutes, stirring every minute, until it looks glossy, has browned spots, and feels almost tender when you press it with the spoon.

Add the bell pepper and the scallion whites to the skillet. Cook for 2 minutes, stirring often, until the pepper starts to soften but still keeps some bite.

Add the garlic to the skillet. Stir for about 30 seconds, just until it smells fragrant and does not brown.

Finish the stir-fry: Stir the sauce again so the cornstarch is evenly mixed, then pour it into the skillet.