Wash and roughly chop 500 grams of ripe tomatoes. Set aside.
In a deep pan, heat 1 tablespoon of butter over medium heat. Add 1 finely chopped onion and 2 minced garlic cloves. Sauté until the onions turn translucent.
Add the chopped tomatoes, 1 teaspoon of sugar, and 1/2 teaspoon of salt. Cook for 10-12 minutes, stirring occasionally, until the tomatoes are soft and mushy.
Remove the pan from heat and let the mixture cool down slightly. Then, blend the mixture using a hand blender or mixer grinder until smooth.
Strain the blended mixture through a sieve to remove the tomato skin and seeds. Discard the residue.
Pour the strained tomato puree back into the pan and add 2 cups of water. Bring the soup to a boil.
Add 1/4 teaspoon of black pepper powder and adjust the salt if needed. Simmer the soup for 5-7 minutes.
In a small bowl, mix 1 tablespoon of cornflour with 2 tablespoons of water to make a slurry. Add this slurry to the soup while stirring continuously to thicken the soup.
Cook for another 2-3 minutes, then turn off the heat. Optionally, you can add a splash of fresh cream for a richer taste.
Garnish the tomato soup with chopped fresh coriander leaves and serve hot with croutons or breadsticks.