In a large pot, over medium heat melt 2 tbsp butter
Add the onion, garlic, and carrots
Stir and cook until tender, about 5-7 minutes
Add tomato paste, stir, and cook another 2-3 minutes
Add the canned tomatoes, chicken broth, and parmesan cheese
Stir together, bring to a boil, reduce the heat, cover and simmer 20 minutes
Use an immersion blender or an upright blender and puree until smooth
Stir in heavy cream
Taste and add salt, if needed
Spread 1 Tbsp mayonnaise on one side of each piece of bread
Put half of grated cheese and two slices of bacon between two pieces of bread and the other half of the cheese and the other two slices of bacon between the other two pieces of bread