Heat oil in large pot over medium-high heat. Add onion. Cook, stirring, for 3 minutes or until light golden. Add pumpkin and 2 tablespoons water. Cook, stirring, for a further 2 minutes.Â
Stir in pasta, milk, stock and ½ cup hot water and bring to a simmer. Reduce heat and simmer, uncovered, stirring occasionally, for 8 minutes. Â
Stir in zucchini. Simmer, stirring occasionally, for a further 2-3 minutes or until pasta and vegetables are tender and sauce is thick and creamy. Â
Remove from heat, gradually add cheese, stirring until melted between additions. Serve seasoned with freshly ground pepper. Â