Rainbow Roasted Vegetables

medium/large red bell pepper, trimmed, seeded, and diced into 1-inch pieces

extra-large carrot, peeled and sliced into thin rounds

medium/large orange or yellow bell pepper, trimmed, seeded, and diced into 1-inch pieces

about 3 cups broccoli florets

half of one medium red onion, sliced into 1-inch wedges

to 3 tablespoons olive oil

to 2 teaspoons kosher salt, or to taste

freshly ground black pepper, or to taste

fresh parsley, optional for garnishing  (see Notes below for additional options and ideas)