Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish.

Heat olive oil and 1 tablespoon of butter in a large skillet over medium-high heat. Add the chopped mushrooms and cook until their liquid is released and evaporated, and they begin to brown (about 8-10 minutes).

Stir in the minced garlic and chopped sage, cooking for another minute until fragrant. Remove from heat.

In a mixing bowl, combine the cooked mushroom mixture, crumbled chestnuts, ricotta cheese, and half of the Parmesan cheese. Season generously with salt and pepper. Mix well.

To make the sauce, melt the remaining 3 tablespoons of butter in a saucepan over medium heat. Whisk in the flour and cook for 1 minute without browning.

Gradually whisk in the milk to avoid lumps. Simmer gently for 5 minutes until thickened. Season with salt and pepper.

Lay out the fresh pasta sheets on a clean surface. Spread the mushroom and chestnut filling evenly over the sheets, leaving a small border at the edges.

Roll the pasta sheets up tightly to form logs. Using a sharp knife, slice the logs into rounds approximately 1.5 to 2 inches thick.

Pour about half of the white sauce into the bottom of the prepared baking dish. Arrange the pasta rolls cut-side up in the dish, packing them gently close together.

Drizzle the remaining sauce over the top of the rolls and sprinkle with the remaining Parmesan cheese.

Bake for 30-35 minutes until the pasta is tender and the top is bubbly and golden brown. Let sit for 5 minutes before serving.