Roast the squash. Preheat your oven to 200°C (180°C fan). Tumble the cubed butternut squash onto a large baking tray. Drizzle with the olive oil, season generously with salt and pepper, and toss to coat. Spread into a single layer. Roast for 25-30 minutes, until the edges are caramelised and the flesh is tender when pierced with a fork. The kitchen will fill with a sweet, nutty scent. Set aside to cool slightly.

Cook the pasta. While the squash roasts, bring a large pot of salted water to a rolling boil. Add the macaroni and cook for 2 minutes less than the package directions suggest. You want it quite al dente, as it will continue to cook in the oven. Drain it, reserving a cup of the pasta water, and set aside.

Infuse the butter with sage. In a large, heavy-based saucepan, melt the butter over a medium heat. Add the chopped onion and cook for 5-7 minutes, or until it becomes translucent and soft. You’ll hear a gentle sizzle. Add the minced garlic and the chopped sage, stirring for another minute until the garlic is fragrant and the sage releases its earthy, almost peppery aroma.

Make the roux. Sprinkle the flour over the onion and sage mixture. Stir continuously for 2 minutes, cooking the flour until it forms a pale, bubbling paste. This is your roux; it should smell nutty and look like wet sand. The colour will be a very light gold.

Build the sauce. Gradually pour in the milk, a little at a time, whisking constantly to prevent lumps. Once all the milk is incorporated, add the stock. Continue to whisk over a medium heat until the sauce thickens enough to coat the back of a spoon. This will take about 5-7 minutes. Listen for the change in sound as it thickens, from a sloshing to a gentle, slow bubble.

Finish the sauce. Remove the pan from the heat. Stir in the grated cheddar and half of the Parmesan cheese until they are fully melted and the sauce is silky. Grate in a pinch of nutmeg, then taste and adjust the seasoning with salt and pepper. The texture should be smooth and glossy.

Assemble the bake. Add the drained pasta and the roasted butternut squash to the sauce. Stir gently until everything is evenly coated. If the sauce seems a little thick, add a splash of the reserved pasta water to loosen it. The mixture should look creamy and inviting.

Top and bake. Pour the mixture into a 9x13 inch baking dish. In a small bowl, combine the breadcrumbs with the remaining Parmesan cheese. Sprinkle this mixture evenly over the top. Dot with a few whole sage leaves for extra fragrance and visual appeal. Bake for 25-30 minutes, until the filling is bubbling around the edges and the top is a deep, crunchy golden brown. The sound of the bubbles breaking through the crust is the sound of success.

Rest and serve. Remove from the oven and allow the bake to rest for 10 minutes. This is crucial; it lets the sauce settle and firm up slightly, making it much easier to serve. The steam that rises as you cut into it will carry the final, perfect note of sage and nutty squash.