Place pork in boiling water for 2 minutes. Remove and pat dry. Mix with marinade of egg yolk, salt, soy sauce and five-flavor spice and let stand for 15 minutes.
Coat pork with cornstarch. Heat oil (360 degrees) and deep fry pork until light brown. Remove. Drain on absorbent paper.
Heat 3 tablespoons oil, stir-fry garlic, onion, green pepper and carrot on high for a few minutes, then add sugar, catsup and vinegar. When just boiling, add cornstarch mixture, stirring constantly until thickened.
Add fried pork and pineapple. Stir briefly. Serve hot. Serves 2 as a main course or 4 to 6 Chinese style.