Step 1: Roast the sweet potatoes

Preheat your oven to 400°F (200°C). Scrub the sweet potatoes, then pierce them a few times with a fork. Rub each sweet potato with olive oil and season with a pinch of salt and pepper. Place them on a baking sheet lined with parchment paper. Roast for 45-60 minutes, depending on their size, until the skins are crispy and the insides are soft and tender when pierced with a fork. Once done, remove them from the oven and let them cool slightly.

Step 2: Caramelize the onions

While the sweet potatoes are roasting, heat 2 tablespoons of olive oil or butter in a large skillet over medium heat. Add the thinly sliced onions and a pinch of salt. Cook the onions, stirring occasionally, for about 25-30 minutes until they are golden brown and fully caramelized. Stir in the balsamic vinegar during the last few minutes of cooking to enhance the flavor. Set the caramelized onions aside.

Step 3: Prepare the hazelnut pesto

While the onions are caramelizing, make the hazelnut pesto. Start by toasting the hazelnuts in a dry skillet over medium heat for 3-5 minutes until they become golden and fragrant. Let the hazelnuts cool, then transfer them to a food processor. Add the fresh basil, parsley, garlic, Parmesan cheese (if using), and lemon juice. Pulse a few times to break down the ingredients. With the motor running, slowly drizzle in the olive oil until the pesto reaches a thick, smooth consistency. Season with salt and pepper to taste. If you prefer a thinner pesto, you can add a little more olive oil or a tablespoon of water.

Step 4: Assemble the stuffed sweet potatoes

Once the sweet potatoes are cool enough to handle, slice each one open lengthwise, being careful not to cut all the way through. Gently fluff the sweet potato flesh with a fork to create space for the toppings. Divide the caramelized onions evenly among the sweet potatoes, stuffing them into the center. Tear the burrata into pieces and place it on top of the onions.

Step 5: Drizzle with hazelnut pesto and garnish

Spoon generous dollops of the hazelnut pesto over each stuffed sweet potato. Garnish with fresh thyme or rosemary for an aromatic touch. For extra crunch, sprinkle some chopped toasted hazelnuts over the top. Serve immediately while the burrata is still soft and creamy.