Prepare Tribeca Oven Multigrain Loaf per package instructions. Dice into ¼” cubes, then bake until toasted. Set aside for service.
Lemon Basil Vinaigrette: in a blender, combine lemon juice, basil, garlic, and Dijon mustard. While blending, stream in extra virgin olive oil until emulsified. Season to taste. Set aside for service. Cover, label, date, and refrigerate.
Reduce balsamic vinegar by half. Set aside for service in a squeeze bottle. Cover, label, date, and refrigerate.
For service, per order: drizzle lemon basil vinaigrette onto croutons to lightly soften (about 2 tsp.). Meanwhile, in a mixing bowl per serving, toss together heirloom tomatoes, basil, pickled red onion, and balsamic reduction. Combine with soaked croutons and gently toss together. Plate and garnish with additional balsamic reduction.