Preheat your oven to 180 deg C and line a baking tray with baking paper.
Toss the pumpkin in the olive oil and salt, place on a baking tray and cook for 45-50 mins until tender. Set aside to cool completely. Saute the onion and garlic in a hot pan for a few mins until softened. Set aside.
In a food processor add the cooked, cooled pumpkin, onion and garlic, parsley, eggs, Parmesan, pepper and nutmeg. Process to form a smooth paste and set aside.
Cook the pasta until al dente, drain and toss through the pumpkin mixture in a separate bowl. Add the feta and peas and stir through again. Pour the pasta into a 25cm x 35cm baking dish and set aside.
To make the béchamel heat the butter over a medium to high heat. Slowly add the flour until roux forms. Cook for a few mins, continually stirring. Slowly add the milk and whisk until the mixture has thickened completely (approx. 10 mins). Add the grated Parmesan, nutmeg and pepper and stir again. Pour the béchamel over the pasta, ensuring it is evenly covered, add a little extra grated Parmesan and bake for 45-50 mins in the oven.
Allow to cool down for half an hour before serving with a Green salad.