Heat oil in a large saucepan over medium-high heat. Add onion. Cook, stirring, for 3 to 4 minutes or until onion has softened.

Add pumpkin, cauliflower, simmer sauce and stock. Bring to the boil. Reduce heat to low. Simmer, covered, stirring occasionally, for 20 minutes or until vegetables are tender.

Add spinach and lentils to pan. Cook for 2 minutes or until spinach is wilted and lentils heated through. Serve curry with rice.