Stuffing - Heat oil in a pan and add the onion, ginger, garlic and green chilies. Saute till they turn light brown.
Add the mince, sambal paste and all the powdered spices. Stir fry till well cooked. Switch off the flame and mix it with the beaten egg, a pinch each of salt and pepper.
Heat a pan and toast the buns (cut through lengthwise, but still intact). Keep aside. In the same pan heat 1 tsp. oil and pour in half of the egg-mince mix.
Place an open faced bun over the top and press it gently with the spatula. Tuck in the omelette and when one side is done, gently flip it over and toast the other side too.
Garnish with tomato sauce, spring onions and coriander leaves. Make another Roti John with the remaining egg mix and enjoy for breakfast a la Singaporean style.