Cook the pasta: Bring a large pot of salted water to a boil. Add pasta and cook until al dente according to package directions.
Drain and rinse under cool water to stop cooking, then let it drain well.
Make the creamy dressing: In a blender or food processor, combine cottage cheese, Greek yogurt, olive oil, lemon juice, Dijon, garlic, salt, and pepper. Blend until completely smooth and creamy. Taste and adjust seasoning with more salt, pepper, or lemon.
Prep the vegetables: While the pasta cools, chop tomatoes, cucumber, bell pepper, and onion.
If using frozen peas, thaw under warm water and drain.
Combine: In a large bowl, add the cooled pasta, vegetables, peas, and dill. Pour in the dressing and toss until everything is evenly coated.
Add cheese and extras: Fold in the Parmesan and any optional proteins or add-ins. If the salad looks thick, splash in 1–2 tablespoons of water or a bit more lemon juice to loosen.
Chill: Cover and refrigerate for at least 30 minutes to let flavors meld.
Stir again before serving and adjust seasoning if needed.
Serve: Garnish with extra dill, black pepper, and a drizzle of olive oil if you like. Serve cold or at cool room temperature.