Prepare macaroni according to package directions. Drain and keep warm.
Heat the vegetable alfredo sauce in large saucepan over med-high heat until smooth and bubbling. Stir in cauliflower/broccoli and heat through. Remove from heat and add cheddar cheese and mustard. Stir gently until cheese melts. Add cooked pasta and return to heat. Cook, stirring gently, until warmed through. Serve immediately.