A streamlined way for making a colorful vegetable casserole

This undated photo provided by America's Test Kitchen in July 2018 shows a vegetable and orzo tian in Boston. This recipe appears in the cookbook “Dinner Illustrated.” (Steve Klise/America's Test Kitchen via AP)

This colorful vegetable casserole has a striking look but a simple approach. A tian is an assortment of roasted vegetables cooking in a shallow dish, sometimes with cheese or au gratin.