Preheat your oven to 375°F. Lightly coat a baking sheet with nonstick cooking spray.

Spread the bread cubes in a single layer on the prepared sheet. Bake until dry and just starting to brown at the edges, about 7 to 10 minutes. Transfer the cubes to a medium bowl.

In a small bowl, mix together the melted butter, minced garlic, chopped sage, Parmesan, and salt. Pour this mixture over the bread cubes and toss well to coat evenly.

Return the coated croutons to the baking sheet. Bake until golden brown and crispy, about 5 to 10 more minutes. Remove from the oven and set aside to cool.

In a large pot, combine the olive oil, minced garlic, salt, and crushed red pepper flakes. Heat over medium heat, stirring, until the garlic is fragrant, about 1 minute.

Stir in the crushed tomatoes and vegetable broth. Bring the mixture to a boil, then reduce the heat to a simmer. Cook for 10 minutes, stirring occasionally.

Remove the pot from the heat. Stir in the chopped basil and heavy cream until well incorporated. Season with salt and freshly ground black pepper to taste.

Ladle the soup into bowls and top generously with the garlic and sage croutons. Serve hot.