Roasted Cauliflower with Indian Barbecue Sauce

Preheat oven to 400°F. Toast cumin in small skillet over medium heat until darker in color and beginning to smoke, about 11/2 minutes. Set aside. Toss cauliflower and 2 tablespoons oil in large bowl. Transfer to medium rimmed baking sheet. Roast until very tender, stirring occasionally, about 45 minutes. Meanwhile, heat remaining 2 tablespoons oil in small saucepan over medium-low heat. Add ginger and garlic; sauté until very fragrant, about 3 minutes. Add ketchup, soy sauce, sugar, and toasted cumin. Bring to boil, whisking to blend. Reduce heat to very low; simmer barbecue sauce 1 minute to blend flavors, whisking constantly. Remove cauliflower from oven; transfer to large bowl. Toss with enough barbecue sauce to coat; season to taste with salt and pepper.