Arrange the pumpkin cubes on a baking tray covered with parchment paper.
Drizzle the extra-virgin olive oil over the top and add thyme sprigs and garlic.
Roast in a preheated oven to 360°F/180°F for about 30 min or until soft and cooked through.
In a large pot of lightly salted boiling water cook the pasta al dente, about 2 mins before cooking time.
While pasta cooks, prepare the sauce. In a large sauce pan melt the butter over medium-low heat. Slowly add flour, while whisking the mixture until fully combined. Add the bay leaf in.
Gently whisk the milk in a little at the time, until you have a smooth even sauce. Continue to whisk and simmer on low heat until the sauce thickens a little, then turn the heat off. Season with a pinch of nutmeg and salt and pepper to taste.
Transfer the sauce and ⅔ of roasted pumpkin cubes (add the garlic if you like) in a blender or food processor. Pulse until creamy and fully combined.
Drain the pasta al dente and transfer back in the pot. Pour in the pumpkin bechamel sauce, add comte cheese and half parmesan cheese and mix until combined.
Transfer the pasta mixture into a large baking dish or individual casserole dishes, Scatter over the top the remaining parmesan cheese and pumpkin cubes, and the breadcrumbs.
Season with freshly-cracked black pepper and bake in a preheated oven to 360°F/180°C for about 20 min or until crispy and golden on top.
Serve immediately, store leftovers in an airtight container and refrigerate for up to 3 days.
You can also freeze your mac and cheese before baking – defrost thoroughly before cooking. Substitute comte and parmesan cheese with your favorite cheese if you like - gruvyer, mature cheddar, fontina are all good options.