In a small bowl, whisk together soy sauce, sugar, chili paste, garlic and ginger.
Cut chicken breasts in half horizontally. Place in a freezer bag. Add half of the sauce mixture. reserve the rest.
Close the freezer bag and place in a fridge for 6 to 24 hours to marinade.
Preheat oven to broil.
Line a large baking sheet with aluminum foil and arrange chicken on sheet. Broil chicken for 4 to 5 minutes on each side, until done. The inside should no longer be pink and the juices run clear.
While chicken is broiling, pour remaining sauce mixture in a medium saucepan and cook over medium heat for 3 to 4 minutes, until it thickens a little and is slightly reduced. Remove from heat and keep to serve with finished dish.
Drizzle cooked chicken with sauce.
Notes
Mary recommends using at least 3 tablespoons of chili paste to truly make this a sweet and spicy flavor combo. You can go up to 6 tablespoons, depending on your preferences.I halved the recipe for our family but feel free to use full amounts, as stated in the cookbook.