Step 1: Prepare the Sweet Potato Crostini

1. Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper.
2. Slice the sweet potatoes into ¼-inch rounds, aiming for uniform thickness to ensure even roasting.
3. Arrange the sweet potato rounds on the prepared baking sheet in a single layer.
4. Drizzle olive oil over the sweet potato slices, then season with sea salt flakes and freshly ground black pepper.
5. Roast in the preheated oven for 20-25 minutes, flipping halfway through, until golden and crispy on the edges. Remove from oven and let cool slightly.

Step 2: Make the Sage Walnut Pesto

1. In a food processor, combine sage leaves, parsley, toasted walnuts, Parmesan cheese, and garlic.
2. Pulse until finely chopped, then slowly drizzle in the olive oil while processing until the mixture becomes a smooth pesto.
3. Season with salt and pepper to taste. Set aside.

Step 3: Assemble the Crostini

1. Once the sweet potato rounds are slightly cooled, spread a small dollop of sage walnut pesto on each slice.
2. Top each round with a tear of burrata cheese.
3. Add a small spoonful of cranberry sauce over the burrata.

Step 4: Garnish and Finish

1. Sprinkle each crostini with finely chopped rosemary and a pinch of sea salt flakes for added flavor and presentation.
2. Garnish with fresh sage leaves for a festive, aromatic touch.

Step 5: Serve

1. Arrange the crostini on a serving platter and serve immediately while the sweet potatoes are warm and the burrata is creamy.