In a large saucepan, heat up 1 tbsp olive oil over medium-high heat.
Stir fry the garlic and onion until fragrant.
Add in tomato paste and stir fry to bring out the flavours (this step is crucial).
Add in the tomatoes and keep on stir frying until the tomatoes are mushy and the liquids are released by pressing down on it.
Add ketchup, sugar, salt, white pepper and mix.
Pour in chicken stock and bring to a boil. Then simmer over low heat and cook for 15 minutes.