Place chicken in a medium bowl. Add egg, cornstarch, 1/2 of the minced garlic, 1/2 of the minced ginger, salt, and 1/2 teaspoon black pepper. Mix until chicken is completely coated. Heat oil in a deep skillet and fry chicken pieces until no longer pink in the center and the juices run clear, 7 to 10 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C). Set fried chicken aside. Heat 2 tablespoons oil in a second skillet over medium heat. Add cumin seeds and cook until crackling, about 1 minute. Add remaining garlic, remaining ginger, serrano peppers, cumin, chile powder, 1/2 teaspoon black pepper, and salt. Add curry leaves and stir to combine. Add chile-garlic paste, ginger paste, and red food coloring. Stir to create a paste. Add water to thin paste slightly. Add fried chicken to the the skillet and toss to coat thoroughly. Stir in cilantro.