Cook carrot in a saucepan of boiling water for 15-20 minutes or until tender. Using a slotted spoon, transfer to a food processor. Add cauliflower to same pan and cook for 10 minutes until tender. Add corn and cook for 2 minutes. Drain. Process carrots until smooth.
Cook pasta in a saucepan of salted boiling water until just tender. Drain and return to pan. Add cauliflower and corn and stir well.
Meanwhile, melt spread in a saucepan over medium heat. Stir in flour. Cook for 1 minute. Remove from heat and gradually stir in milk until combined. Return to heat and cook, stirring constantly, until mixture comes to the boil. Reduce heat and simmer for 2 minutes. Set aside.
Add carrot purée, cheese and half the parmesan. Pour mixture over pasta and stir to combine. Season. Transfer mixture to a 12-cup capacity ovenproof dish. Sprinkle with tasty cheese.
Bake for 30-35 minutes or until golden. Serve macaroni with rocket.