Roasted butternut and rosemary lasagne

Preheat the oven to 220 °C and grease an ovenproof dish.
Cut the butternut into small blocks and arrange in a single layer in a separate oven pan.
Drizzle with the oil and season to taste with salt and pepper.
Roast for 15 minutes and set aside until needed.
Sauce:
Melt the butter in a large saucepan, add the garlic and sauté until soft.
Stir in the flour and stir-fry for one minute.
Gradually beat in the milk and heat until the sauce starts simmering and thickens slightly.
Add the rosemary, sage and nutmeg and season with salt and pepper.
Sheets:
Cook the lasagne sheets in boiling water for about five minutes and cook only a few sheets at a time.
Drain and carefully arrange the sheets on a tea towel.
To make the lasagne:
Spoon a third of the sauce in the bottom of the greased dish and arrange a layer of the lasagne sheets on top.
Scatter half the butternut on top of the lasagne.
Repeat the layers, ending with a layer of sauce, ensuring the last layer of lasagne is completely covered with the sauce to prevent it from drying out.
Leave the dish to rest for one hour so the pasta can soften before baking it at 180 °C for about 40 minutes. Serve hot.