According to the package directions, cook the pasta, drain, and set aside.
Microwave the leeks in a covered, microwave safe bowl on high for 2 to 3 minutes, or until lump and translucent. Add the mussels and cayenne pepper to the leeks and stir. Recover and microwave on high for 30 seconds to heat the mussels.
Next, combine the oregano, cottage cheese, yogurt, and Parmesan cheese in a blender until smooth. Combine the cottage cheese and mussel mixtures and microwave on high for about 30 seconds to warm.
Toss the pasta with olive oil, and then stir in the mussel mixture. Divide into roughly 4 equal portions and serve immediately topping with cracked black pepper, if desired.