Creamy Tomato Bisque with Brie Croutons

Name: Creamy Tomato Bisque with Brie Croutons
Ingredients: 1 small yellow onion; 6 cloves garlic; 1 (28-ounce) can whole peeled tomatoes; 2 cups water; 4 tablespoons (1/2 stick) unsalted butter; 2 tablespoons rice flour (non-glutinous); 2 tablespoons tomato paste; 1 tablespoon Italian seasoning; 2 1/2 teaspoons kosher salt, plus more as needed; 2 teaspoons granulated sugar, plus more as needed; 1 teaspoon fennel seeds; 1/2 to 1 teaspoon red pepper flakes (optional); 1/2 cup heavy cream; 1/2 baguette (about 6 inches); 4 ounces Brie cheese; Freshly ground black pepper, for serving (optional)