Several hours ahead or a day before, cut baguette into 24 cubes, about 2 to 2 1/2 inches each. Place cubes on a baking sheet. Preheat oven to 400 degrees, letting it heat through at least 2 cycles (let the thermostat light go out, come on again, and go out again). Put baking sheet on center rack of oven, close door and turn off heat. Let cubes sit in oven to dry out for up to 8 hours. They will take on a bit of color. Set aside.
In a large nonreactive saucepan, heat oil over medium-low heat. Add garlic and cook, covered, 30 minutes, stirring occasionally, until very soft and begging to turn golden. Raise heat to medium, uncover and continue cooking, stirring frequently, 5 minutes or until a deep golden color.
Add broth, tomatoes, and white pepper. Bring to a boil over medium-high heat and let simmer about 10 minutes. Stir in cheese and remove from heat.
Place 4 bread cubes in each of 6 warm serving soup plates. Divide julienned basil leaves among them. Then, divide hot soup among 6 soup plates. Serve immediately.
Makes: 6