Preheat oven to 375°F (190°C). Lightly spray casserole dish. Combine garlic powder, black pepper, seasoning and salt with yogurt. In large bowl toss yogurt mixture with squash, shallots and green onions. Pour into casserole dish and top with breadcrumbs mixed with parsley or chives. Bake uncovered for 30-45 minutes or until golden brown on top and bubbling.
To make fresh breadcrumbs, cut away crusts of coarse textured bread. Crumble the bread into a food processor and pulse to the desired consistency. For dried crumbs, dry fresh crumbs in an oven set on 200°F (95°C) for about 30-45 minutes.