Bring a medium pot of water to boil. While water is boiling, make criss-cross cuts on top if tomatoes, just enough to break the skin. Place tomatoes, top up, in a colander. Pour boiling hot water, slowly, over tomatoes. After that you will be able to pill the skin off tomatoes very easily with your hands. Peel all tomatoes.
Preheat a medium pot on medium heat and add olive oil.
Chop onion and tomatoes and add them to the pot.
Add bay leaf, salt, pepper and sugar. Stir well and cover. Once it starts to low boil, turn the heat down to medium low and cook, covered and stirring occasionally, for 25-30 minutes.
Take out bay leaf and transfer the mixture into the food processor. Blend until smooth. Mix soft butter and flour until it makes smooth paste (roux) and add it to the blender. Add heavy cream and blend all well.
Transfer back to the pot, stir in minced basil, cover and cook for a few more minutes.
Cut the bread and cheese into thin slices and make the grilled cheese sticks.