Step 1: Roast the Sweet Potatoes

1. Preheat the oven to 400°F (200°C).
2. Wash and scrub the sweet potatoes thoroughly. Pat them dry and prick each potato several times with a fork.
3. Rub each sweet potato with olive oil, and season generously with salt and pepper.
4. Place the sweet potatoes on a baking sheet lined with parchment paper or foil.
5. Roast in the preheated oven for 45-60 minutes, or until the sweet potatoes are soft and caramelized, with a knife easily piercing through the center.

Step 2: Make the Sage Pesto

1. While the sweet potatoes are roasting, prepare the sage pesto.
2. In a food processor, combine the sage leaves, parsley, grated Parmesan, pine nuts (or walnuts), and minced garlic.
3. Pulse until the ingredients are finely chopped. With the motor running, slowly drizzle in the olive oil until the mixture forms a smooth but slightly textured pesto.
4. Add lemon juice, salt, and pepper to taste. Adjust seasoning as needed. Set aside.

Step 3: Toast the Walnuts

1. In a small skillet over medium heat, melt the butter.
2. Add the chopped walnuts and toast, stirring frequently, until fragrant and golden brown, about 3-4 minutes. Be careful not to burn them.
3. Remove from heat and let cool.

Step 4: Assemble the Stuffed Sweet Potatoes

1. Once the sweet potatoes are done roasting, remove them from the oven and let them cool slightly.
2. Slice each sweet potato lengthwise, being careful not to cut all the way through.
3. Fluff the interior of each potato with a fork, creating a small pocket for the toppings.

Step 5: Add Burrata and Pesto

1. Place chunks of burrata inside each sweet potato, allowing the creamy center to melt slightly from the residual heat.
2. Drizzle each potato generously with the sage pesto.
3. Sprinkle the toasted walnuts over the top, adding crunch and a nutty depth.

Step 6: Garnish and Serve

1. Garnish with fresh sage leaves and a light drizzle of honey or balsamic glaze for a touch of sweetness and acidity, if desired.
2. Finish with a few cracks of freshly ground black pepper and serve immediately.