Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Dice the sugar pumpkin into even one-inch cubes and place them on the baking sheet alongside the chicken breast.
Drizzle the pumpkin and chicken with olive oil and season both sides evenly with garlic powder, sea salt, and black pepper.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the pumpkin is fork-tender.
While the tray roasts, melt the ghee in a small skillet over medium heat, whisking constantly until it turns a deep golden brown and smells toasted.
Stir the fresh chopped sage into the browned ghee for 30 seconds until the leaves are crisp, then remove from heat immediately to prevent burning.
Slice the roasted chicken and serve over a bed of fresh baby spinach with the pumpkin, drizzling the warm sage butter over everything and finishing with a sprinkle of parmesan.