Make the dressing: In a mixing bowl, whisk together the dressing ingredients until smooth. Season to taste with salt and pepper.
Preheat an oven to 400 degrees F. Line a baking sheet with parchment paper and spread the torn bread in an even layer. Drizzle with olive oil and sprinkle with salt and pepper. Toss until the bread is evenly coated. Toast in the oven for 8-10 minutes, until the edges of the bread start to turn golden brown. Cool slightly.
Assemble your salad: In a large serving bowl, gently toss together the tomatoes and onion with the vinaigrette. Marinate for 10 minutes. Add the remaining ingredients, including the bread, and toss to coat in the vinaigrette. Toss with freshly torn basil leaves and serve immediately.