Mix the sugar, sesame oil, sherry, soy sauce, 1 teaspoon cornstarch in a bowl and add the chicken. Set aside.

Mix the remaining cornstarch with the water and set aside.

Heat a large skillet over high heat and add 1 tablespoon vegetable oil. Add the onions and stir fry for 1 min. Add the garlic and ginger and then add the broccoli, 2 tablespoons of water and stir fry ~2 minutes until broccoli is green but crisp. Move to another container.

Using the skillet, add 2 tablespoons vegetable oil and cook the chicken ~3 minutes. Add broccoli, heat, and then add the reserved water with cornstarch. Serve with rice.