Preheat oven to 190C or 170C fan. Place pumpkin, bacon, garlic and half of oil in a baking pan and toss to coat. Cook for 30-40 minutes, until pumpkin is tender. Squeeze garlic from skin.
Meanwhile cook pasta in a large saucepan of boiling, salted water according to packet directions. Drain, reserving 1 cup of cooking liquid.
Combine pasta, pumpkin, bacon, garlic flesh, fetta, parsley and remaining oil in a 10-cup ovenproof dish. Pour over reserved liquid and top with mozzarella. Bake for 25 minutes, until golden.