In a small saucepan heat the butter with the oil, the curry powder, and salt and pepper to taste over moderately low heat, stirring, until it is melted and in a roasting pan just large enough to hold the squash in one layer toss the squash with the curry mixture until it is coated well. Roast the squash in the middle of a preheated 375F. oven, shaking the pan occasionally, for 25 minutes, or until it is tender. Season the squash with salt and pepper, add the coriander, and toss the mixture gently. Serves 6. Gourmet October 1992