Preheat the oven to 200°C. Wash, dry, and cut the squash in half lengthwise. Remove the seeds and stringy parts. Cut the flesh into slices.
Brush the slices with olive oil using a pastry brush if you have one, and arrange them in a single layer on a baking mat or, if you don’t have one, on the oven rack lined with parchment paper. Season with salt and pepper.
Wash and peel the potatoes. Cut the larger ones in half. Place them in a bowl with the oil, salt, and pepper. Toss to coat, then transfer them to a baking dish.
Bake the squash and potatoes for 30 minutes.
Preparing the filet mignons
Peel and chop the onion and the garlic (with the germ removed). Heat the butter in a Dutch oven. Brown the tenderloins for 10 minutes, turning them regularly. Remove the meat from the Dutch oven.
Add the chopped onion and garlic, season with salt and pepper, and let them soften and brown over low heat for 5 minutes, then pour in the white wine. Let it reduce for 3 minutes, then stir in the broth. When the liquid is simmering, return the fillets to the pot. Cover and simmer for 30 minutes over low heat.
Whisk together the honey, soy sauce, mustard, ginger, and ground coriander. Remove the tenderloins from the casserole dish and pour in the honey mixture. Let it reduce for 5 minutes, scraping up the pan juices as you go.
Cut the meat into thick slices, drizzle with sauce, and serve with the squash and roasted potatoes.
Notes
You can serve a chicory and watercress salad as an appetizer.