Heat oil over medium heat in a large saucepan. Add onion and garlic and cook until soft.
Sprinkle flour on top. Cook and stir for 1 minute.
Gradually stir in milk, and then both cans of tomatoes, basil, oregano, and chicken broth.
Bring just to a simmer and cook for 15 minutes, stirring frequently.
Preheat oven to 350 degrees.
Cut baguette into 1-inch pieces and toss with olive oil. Place on a baking sheet lined with parchment paper. Place in oven and bake until crispy. Sprinkle cheese on top and return pan to oven until cheese is melted.