1. Place one rack in top third of oven and another in bottom third; preheat to 400 degrees. Line 2 baking sheets with aluminum foil (for easier cleanup). Make spice mixture: In a small bowl, combine chili powder, cayenne pepper, and 1 teaspoon coarse salt; set aside.

2. Place turkey breast on one of the prepared baking sheets. Rub all over with 1 tablespoon oil, then sprinkle with spice mixture, seasoning both under and on top of skin. Roast, skin side up, on lower rack, 25 minutes.

3. Meanwhile, make glaze: In a small bowl or measuring cup, mix molasses with 1 teaspoon coarse salt and remaining 2 tablespoons oil. Lay pieces of squash in a single layer on second prepared baking sheet; brush both sides with some of the glaze.

4. After turkey has roasted 25 minutes, brush skin with some of the remaining glaze. Place squash on upper rack; roast until tender, 30 to 35 minutes. Meanwhile, continue to roast turkey, brushing with glaze every 8 to 10 minutes, until an instant-read thermometer inserted in thickest part of breast registers 165 degrees. 20 to 25 minutes more.

5. Cover turkey loosely with aluminum foil. Let rest 10 minutes before slicing. Serve with squash and, if desired, green beans.