Preheat the oven to 400°F for roasting the butternut squash.
Peel and cube the butternut squash, toss lightly with a drizzle of olive oil, salt, and pepper, then roast on a baking sheet for about 20-25 minutes until tender and slightly caramelized.
Meanwhile, prepare the sweet potato gnocchi by mashing a cooked sweet potato (approx. 150g) until smooth. Mix in the rice flour and egg white until a manageable dough forms, adding a pinch of salt.
On a lightly floured surface, roll the dough into logs and cut into bite-sized pieces. Optionally, press lightly with a fork to create ridges.
Bring a pot of salted water to a boil and gently drop in the gnocchi. When they float to the surface, they are done, about 2-3 minutes. Drain and set aside.
Heat a small skillet with the remaining olive oil and crisp up the fresh sage leaves until they become crispy, careful not to burn them.
In a separate pan, grill a seasoned chicken breast (about 3 oz/85g) until cooked through, then slice into strips.
Combine the gnocchi with the roasted butternut squash and add the grilled chicken strips. Toss gently to mix the flavors.
Top the dish with the crispy sage leaves, season with additional salt and pepper if needed, and serve immediately.