Preheat oven to 400 degrees F. Line two baking sheets with aluminium foil. Spray foil with cooking spray and set aside.
In a small microwave safe bowl, combine the butter and garlic. Melt butter in the microwave for 30-60 seconds, or until butter is fully melted and garlic is fragrant.
In a large bowl, toss together the melted butter, bread cubes, Parmesan cheese, Italian seasoning, salt and black pepper.
Transfer the seasoned bread cubes to one of the prepared baking sheets and bake in a preheated 400 degree F oven for 8-12 minutes, or until toasted and golden brown.
Meanwhile, to prepare salad, in a large bowl toss together the butternut squash, sweet potatoes, Brussels sprouts, garlic, olive oil, salt and black pepper. Spread vegetables in a single layer on the second baking sheet. Roast vegetables in preheated 400 degree F oven for 25-30 minutes, or until golden brown and soft.
While the vegetables roast, prepare balsamic vinaigrette by whisking together olive oil, balsamic vinegar, maple syrup, mustard, salt and black pepper. Set aside.
To assemble salad, in a large bowl, toss together prepared croutons, roasted vegetables, red onion, dried cranberries, arugula and desired amount of balsamic vinaigrette (to start, about 4 tablespoons). Serve immediately.
Cooking Tip: For less dirty dishes, use the same bowl to make croutons, toss veggies in oil and assemble the salad!