Preheat your oven to 400°F (200°C).

Peel the butternut squash, slice it in half lengthwise, remove the seeds, then cut into ¼-inch half-moon pieces.

Trim the tops off the fennel, cut in half, and slice into ¼-inch pieces.

Core and slice the apples into ¼-inch pieces, keeping the skin on.

Sauté shallots in olive oil for 6-8 minutes until soft and caramelized, then spread them in the baking dish.

Layer butternut squash, fennel, and apple slices tightly in the baking dish.

Drizzle ½ cup of olive oil and sprinkle kosher salt over the vegetables.

Cover with foil and bake for 40 minutes.

Uncover and continue baking for 20 minutes.

Combine walnuts and rosemary with remaining olive oil, then spread over the tian and bake for an additional 10-15 minutes.

Let the tian rest for 10 minutes before serving.