Heat up butter in a pan and add the bay leaf. Once it sizzles, add the chopped onion, garlic, and red chilly.
When it gets fried add grated carrots, saute for a minute, and add the chopped tomatoes. Add 1/2 tsp of salt and 1 tsp of sugar and saute for a few minutes.
Add water just enough to immerse the contents of the pan, cover, and cook well. You can opt to transfer the contents to a pressure cooker and cook for 1 whistle.
Once the tomatoes are cooked, cool down, discard the bay leaf and blend smoothly in a mixer/blender.
Strain into a saucepan and reheat adding salt pepper and sugar as is necessary.
Once it comes close to a boil, add the cornflour slurry, made by mixing the cornflour in 1/4 cup of water.
Simmer the flame and cook till it thickens. Add cream at this stage if you are adding. Switch off and serve hot with bread croutons.