Cook the pasta according to the package directions. Drain pasta using a colander over a bowl. Combine shrimp, onions, and garlic in a small bowl. Heat a large skillet over medium-high heat. Add olive oil, swirl to coat. Add shrimp mixture, and saute for 4 minutes or until shrimp are done.
Steam thawed broccoli in microwave for 1 minute or until cooked.
Take cauliflower, half the Parmesan and place in a blender with the milk and blend until creamy. Pour into skillet with shrimp and cooked pasta and begin to heat on low-medium heat for 1 minute. Add pasta water to skillet if sauce is too thick.
Add steamed broccoli to skillet and mix until well coated. Add salt and pepper to taste. Sprinkle with remaining Parmesan cheese.