Bring broth, ginger, corn, soy sauce and white pepper to a simmer in a 4-quart pot. Cook for 4 minutes until the corn is hot.
Mix cornstarch with cold water. Stir the slurry into the simmering broth and cook for 1 minute until lightly thickened.
Gently slide in tofu cubes and heat for 2 minutes without breaking them up. Reduce the heat to a very gentle simmer.
Stir the broth slowly in one direction and pour beaten eggs in a thin stream. Stop stirring for 30 seconds, then gently lift the ribbons and cook for 1 to 2 minutes until eggs are fully set and reach 160°F.
Switch off the heat, stir in sesame oil and divide among 4 bowls. Add the measured scallions evenly over the servings.