Roasted Sweet Potatoes

Preheat oven to 425 degrees F. Coarsely grind coriander, fennel, oregano and red pepper flakes in an electric coffee or spice grinder or with a mortar and pestle . Stir together the spices and salt. Cut potatoes lengthwise into 1-inch wedges. Toss the wedges with oil and spices in a large roasting pan and roast in middle of the oven for 20 minutes. Turn the wedges over with a spatula and roast until tender and slightly golden (15-20 minutes more).