In a blender or food processor, combine the cottage cheese, milk, sour cream, Parmesan cheese, salt and cayenne; cover and process until smooth. Set aside.
In a saucepan, bring 1 in. of water to a boil; place broccoli and cauliflower in a steamer basket over water. Cover and steam for 3-4 minutes or until crisp-tender. Meanwhile, cook pasta according to package directions; drain.
In a large nonstick skillet, saute garlic in oil for 2 minutes.
Add mushrooms; saute 5 minutes longer. Stir in the broccoli, cauliflower, pasta and cottage cheese mixture; heat through.