Heat the soup pot with some cooking oil on medium heat. Add the chopped onion and minced garlic, and sauté until translucent.
Add tomato purée, tomato, stock, applesauce, sweet chili sauce, sambal, kecap, rice wine vinegar and ginger powder. Give everything a good stir and let simmer for 10 minutes.
In the meantime, preheat a frying pan with some cooking oil on medium heat. Crack the eggs in a bowl, add some salt and pepper and beat with a fork until they're even in color.
Pour the eggs into the pan to make the omelette. Once the bottom has set well, flip to cook the other side. Take the omelette out of the pan and slice it into thin strips.
Return to your soup: use the immersion blender to blend until smooth. If you like no bits whatsoever in your soup, strain afterwards to remove any tomato or chili seeds.
Combine the tbsp of cornstarch and 2 tbsp of water in a small bowl and mix well to create a cornstarch slurry. Add the slurry to the soup.
Add the vermicelli. Let simmer for 5 minutes, until the vermicelli has cooked and the soup has thickened.
In the meantime, give the soup a taste. Tomato sweetness varies, and if you're not getting a distinct sweet flavor at this point, you can now add the tbsp of sugar (or more if desired). Stir and taste again. Done!
Ladle the soup into bowls and top with sliced spring onion and omelette strips. Enjoy!