Whisk the dressing ingredients together in a small bowl or shake in a jar with a tight fitting lid. Set aside
Place the bread cubes in a baking pan. Spray lightly with olive oil cooking spray and toss to coat evenly. Bake at 350 degrees for 10 - 15 minutes until the cubes are dry, crisp and just barely browned. Place in a large serving bowl.
Combine the Brussels sprouts, red onion, and bell pepper in a large roasting pan. Add the tablespoon of olive oil and the salt and pepper. Toss to coat evenly.
Roast at 350 degrees for 35 - 40 minutes. The veggies should be tender and lightly browned. Pour the vegetables and any liquid over the bread cubes and toss to combine.
Pour the dressing over the mixture in the serving bowl and toss to coat.
Add the tomato halves and toss once more. Allow to sit at room temperature for at least 30 minutes. Toss again and serve at room temperature.