Preheat oven to 400°F (200°C). Line two baking sheets with parchment paper. Arrange sliced sweet potato planks in a single layer, brush lightly with 1 tbsp extra virgin olive oil, and bake for 10–12 minutes until pliable. Remove from oven and reduce oven temperature to 375°F (190°C).

Heat remaining 1 tbsp olive oil in a large skillet over medium heat. Add minced garlic and sauté for 1 minute until fragrant. Add fresh spinach, season with ¼ tsp salt and ¼ tsp pepper, and cook until fully wilted. Transfer spinach to a colander and press firmly with paper towels to drain all excess water completely.

In a medium bowl, combine ricotta, crumbled feta, grated parmesan, egg, fresh thyme, remaining ¼ tsp salt, and remaining pepper. Stir vigorously until smooth and uniform.

Lightly grease an 8x8-inch baking dish. Place a single layer of slightly overlapping sweet potato planks at the bottom. Spread half of the ricotta cheese mixture over the sweet potatoes. Top with half of the sautéed garlic spinach. Repeat the layers (sweet potato → ricotta → spinach). Finish with a final top layer of sweet potato planks and a light sprinkle of extra parmesan cheese.

Cover dish tightly with aluminum foil. Bake at 375°F (190°C) for 35 minutes. Remove foil and bake uncovered for another 15 minutes until cheese is bubbly and edges are golden and caramelized.

In a small saucepan over low heat, warm raspberry preserves, raw honey, and balsamic vinegar together until smooth and glossy. Remove lasagna from oven and let rest for 15 minutes. Top with toasted walnuts, drizzle warm raspberry honey sauce generously over the crown, garnish with fresh thyme, slice into squares, and serve warm.