Sauté garlic and tomato. In a small pot, heat 1 tablespoon of oil over medium heat until hot. Sauté the garlic, ginger, and white parts of green onions for 30 seconds or until fragrant. Then add the tomato and sauté for 2 to 3 minutes or until softened.
Make the soup. In a small pot, add the chicken broth, chicken bouillon powder, and white pepper. Cover and bring to a boil over medium-high heat. Once it boils, reduce the heat to a simmer.
Make and add the cornstarch slurry. In a small bowl, mix the cornstarch with 3 tablespoons of water to make a slurry. Then slowly pour the cornstarch slurry in while simultaneously stirring the broth. Stir until the soup thickens.
Add the egg ribbons. Slowly stir the broth in a circular motion while simultaneously drizzling in the eggs in a thin stream. It should take about 20-30 seconds to pour in all the eggs. The slower you pour, the thinner and silkier the egg ribbons.
Notes
See the What I Learned From Testing This Recipe section for more guidance.